changeset 150:9283aaf1ffb8

implemented optimised FFT via the Accelerate framework. closes #5
author Jamie Bullock <jamie@jamiebullock.com>
date Wed, 09 Jan 2013 23:09:34 +0000
parents 0881cd514c9c
children 38c00d1d5396
files src/Makefile.am src/fft.h src/fftsg.c src/fftsg.h src/helper.c src/init.c src/scalar.c src/vector.c src/window.c src/xtract_globals_private.h xtract/xtract_scalar.h
diffstat 11 files changed, 405 insertions(+), 3658 deletions(-) [+]
line wrap: on
line diff
--- a/src/Makefile.am	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/Makefile.am	Wed Jan 09 23:09:34 2013 +0000
@@ -1,11 +1,28 @@
 MAINTAINERCLEANFILES = Makefile.in
 
-SOURCES = libxtract.c descriptors.c scalar.c vector.c delta.c init.c\
-	window.c fini.c helper.c fftsg.c
+if BUILD_OOURA
+OOURA = ooura/fftsg.c
+else
+OOURA =
+ACCELERATE_FLAGS = -framework Accelerate
+endif
+
+SOURCES = libxtract.c \
+	  descriptors.c \
+	  scalar.c \
+	  vector.c \
+	  delta.c \
+	  init.c \
+	  window.c \
+	  fini.c \
+	  helper.c \
+	  $(OOURA)
 
 lib_LTLIBRARIES = libxtract.la
-libxtract_la_CFLAGS = $(FFT_DEFINE)
+libxtract_la_CFLAGS =
 libxtract_la_SOURCES = $(SOURCES)
-libxtract_la_LDFLAGS = -export-dynamic
+libxtract_la_LDFLAGS = -export-dynamic $(ACCELERATE_FLAGS)
 
-EXTRA_DIST = xtract_globals_private.h xtract_macros_private.h xtract_window_private.h
+EXTRA_DIST = xtract_globals_private.h \
+	     xtract_macros_private.h \
+	     xtract_window_private.h
--- a/src/fft.h	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/fft.h	Wed Jan 09 23:09:34 2013 +0000
@@ -21,4 +21,34 @@
  *
  */
 
+#ifndef FFT_H
+#define FFT_H
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifdef USE_OOURA
 #include "ooura/fftsg.h"
+#else
+#include <Accelerate/Accelerate.h>
+#endif
+
+#ifdef USE_OOURA
+typedef struct xtract_ooura_data_
+{
+    int *ooura_ip;
+    double *ooura_w;
+    bool initialised;
+} xtract_ooura_data;
+#else
+typedef struct xtract_vdsp_data_
+{
+    FFTSetupD setup;
+    DSPDoubleSplitComplex fft;
+    vDSP_Length log2N;
+    bool initialised;
+} xtract_vdsp_data;
+#endif
+
+#endif /* Header guard */
--- a/src/fftsg.c	Wed Jan 09 20:15:50 2013 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,3492 +0,0 @@
-/*
-Fast Fourier/Cosine/Sine Transform
-    dimension   :one
-    data length :power of 2
-    decimation  :frequency
-    radix       :split-radix
-    data        :inplace
-    table       :use
-functions
-    cdft: Complex Discrete Fourier Transform
-    rdft: Real Discrete Fourier Transform
-    ddct: Discrete Cosine Transform
-    ddst: Discrete Sine Transform
-    dfct: Cosine Transform of RDFT (Real Symmetric DFT)
-    dfst: Sine Transform of RDFT (Real Anti-symmetric DFT)
-function prototypes
-    void cdft(int, int, double *, int *, double *);
-    void rdft(int, int, double *, int *, double *);
-    void ddct(int, int, double *, int *, double *);
-    void ddst(int, int, double *, int *, double *);
-    void dfct(int, double *, double *, int *, double *);
-    void dfst(int, double *, double *, int *, double *);
-macro definitions
-    USE_CDFT_PTHREADS : default=not defined
-        CDFT_THREADS_BEGIN_N  : must be >= 512, default=8192
-        CDFT_4THREADS_BEGIN_N : must be >= 512, default=65536
-    USE_CDFT_WINTHREADS : default=not defined
-        CDFT_THREADS_BEGIN_N  : must be >= 512, default=32768
-        CDFT_4THREADS_BEGIN_N : must be >= 512, default=524288
-
-
--------- Complex DFT (Discrete Fourier Transform) --------
-    [definition]
-        <case1>
-            X[k] = sum_j=0^n-1 x[j]*exp(2*pi*i*j*k/n), 0<=k<n
-        <case2>
-            X[k] = sum_j=0^n-1 x[j]*exp(-2*pi*i*j*k/n), 0<=k<n
-        (notes: sum_j=0^n-1 is a summation from j=0 to n-1)
-    [usage]
-        <case1>
-            ip[0] = 0; // first time only
-            cdft(2*n, 1, a, ip, w);
-        <case2>
-            ip[0] = 0; // first time only
-            cdft(2*n, -1, a, ip, w);
-    [parameters]
-        2*n            :data length (int)
-                        n >= 1, n = power of 2
-        a[0...2*n-1]   :input/output data (double *)
-                        input data
-                            a[2*j] = Re(x[j]),
-                            a[2*j+1] = Im(x[j]), 0<=j<n
-                        output data
-                            a[2*k] = Re(X[k]),
-                            a[2*k+1] = Im(X[k]), 0<=k<n
-        ip[0...*]      :work area for bit reversal (int *)
-                        length of ip >= 2+sqrt(n)
-                        strictly,
-                        length of ip >=
-                            2+(1<<(int)(log(n+0.5)/log(2))/2).
-                        ip[0],ip[1] are pointers of the cos/sin table.
-        w[0...n/2-1]   :cos/sin table (double *)
-                        w[],ip[] are initialized if ip[0] == 0.
-    [remark]
-        Inverse of
-            cdft(2*n, -1, a, ip, w);
-        is
-            cdft(2*n, 1, a, ip, w);
-            for (j = 0; j <= 2 * n - 1; j++) {
-                a[j] *= 1.0 / n;
-            }
-        .
-
-
--------- Real DFT / Inverse of Real DFT --------
-    [definition]
-        <case1> RDFT
-            R[k] = sum_j=0^n-1 a[j]*cos(2*pi*j*k/n), 0<=k<=n/2
-            I[k] = sum_j=0^n-1 a[j]*sin(2*pi*j*k/n), 0<k<n/2
-        <case2> IRDFT (excluding scale)
-            a[k] = (R[0] + R[n/2]*cos(pi*k))/2 +
-                   sum_j=1^n/2-1 R[j]*cos(2*pi*j*k/n) +
-                   sum_j=1^n/2-1 I[j]*sin(2*pi*j*k/n), 0<=k<n
-    [usage]
-        <case1>
-            ip[0] = 0; // first time only
-            rdft(n, 1, a, ip, w);
-        <case2>
-            ip[0] = 0; // first time only
-            rdft(n, -1, a, ip, w);
-    [parameters]
-        n              :data length (int)
-                        n >= 2, n = power of 2
-        a[0...n-1]     :input/output data (double *)
-                        <case1>
-                            output data
-                                a[2*k] = R[k], 0<=k<n/2
-                                a[2*k+1] = I[k], 0<k<n/2
-                                a[1] = R[n/2]
-                        <case2>
-                            input data
-                                a[2*j] = R[j], 0<=j<n/2
-                                a[2*j+1] = I[j], 0<j<n/2
-                                a[1] = R[n/2]
-        ip[0...*]      :work area for bit reversal (int *)
-                        length of ip >= 2+sqrt(n/2)
-                        strictly,
-                        length of ip >=
-                            2+(1<<(int)(log(n/2+0.5)/log(2))/2).
-                        ip[0],ip[1] are pointers of the cos/sin table.
-        w[0...n/2-1]   :cos/sin table (double *)
-                        w[],ip[] are initialized if ip[0] == 0.
-    [remark]
-        Inverse of
-            rdft(n, 1, a, ip, w);
-        is
-            rdft(n, -1, a, ip, w);
-            for (j = 0; j <= n - 1; j++) {
-                a[j] *= 2.0 / n;
-            }
-        .
-
-
--------- DCT (Discrete Cosine Transform) / Inverse of DCT --------
-    [definition]
-        <case1> IDCT (excluding scale)
-            C[k] = sum_j=0^n-1 a[j]*cos(pi*j*(k+1/2)/n), 0<=k<n
-        <case2> DCT
-            C[k] = sum_j=0^n-1 a[j]*cos(pi*(j+1/2)*k/n), 0<=k<n
-    [usage]
-        <case1>
-            ip[0] = 0; // first time only
-            ddct(n, 1, a, ip, w);
-        <case2>
-            ip[0] = 0; // first time only
-            ddct(n, -1, a, ip, w);
-    [parameters]
-        n              :data length (int)
-                        n >= 2, n = power of 2
-        a[0...n-1]     :input/output data (double *)
-                        output data
-                            a[k] = C[k], 0<=k<n
-        ip[0...*]      :work area for bit reversal (int *)
-                        length of ip >= 2+sqrt(n/2)
-                        strictly,
-                        length of ip >=
-                            2+(1<<(int)(log(n/2+0.5)/log(2))/2).
-                        ip[0],ip[1] are pointers of the cos/sin table.
-        w[0...n*5/4-1] :cos/sin table (double *)
-                        w[],ip[] are initialized if ip[0] == 0.
-    [remark]
-        Inverse of
-            ddct(n, -1, a, ip, w);
-        is
-            a[0] *= 0.5;
-            ddct(n, 1, a, ip, w);
-            for (j = 0; j <= n - 1; j++) {
-                a[j] *= 2.0 / n;
-            }
-        .
-
-
--------- DST (Discrete Sine Transform) / Inverse of DST --------
-    [definition]
-        <case1> IDST (excluding scale)
-            S[k] = sum_j=1^n A[j]*sin(pi*j*(k+1/2)/n), 0<=k<n
-        <case2> DST
-            S[k] = sum_j=0^n-1 a[j]*sin(pi*(j+1/2)*k/n), 0<k<=n
-    [usage]
-        <case1>
-            ip[0] = 0; // first time only
-            ddst(n, 1, a, ip, w);
-        <case2>
-            ip[0] = 0; // first time only
-            ddst(n, -1, a, ip, w);
-    [parameters]
-        n              :data length (int)
-                        n >= 2, n = power of 2
-        a[0...n-1]     :input/output data (double *)
-                        <case1>
-                            input data
-                                a[j] = A[j], 0<j<n
-                                a[0] = A[n]
-                            output data
-                                a[k] = S[k], 0<=k<n
-                        <case2>
-                            output data
-                                a[k] = S[k], 0<k<n
-                                a[0] = S[n]
-        ip[0...*]      :work area for bit reversal (int *)
-                        length of ip >= 2+sqrt(n/2)
-                        strictly,
-                        length of ip >=
-                            2+(1<<(int)(log(n/2+0.5)/log(2))/2).
-                        ip[0],ip[1] are pointers of the cos/sin table.
-        w[0...n*5/4-1] :cos/sin table (double *)
-                        w[],ip[] are initialized if ip[0] == 0.
-    [remark]
-        Inverse of
-            ddst(n, -1, a, ip, w);
-        is
-            a[0] *= 0.5;
-            ddst(n, 1, a, ip, w);
-            for (j = 0; j <= n - 1; j++) {
-                a[j] *= 2.0 / n;
-            }
-        .
-
-
--------- Cosine Transform of RDFT (Real Symmetric DFT) --------
-    [definition]
-        C[k] = sum_j=0^n a[j]*cos(pi*j*k/n), 0<=k<=n
-    [usage]
-        ip[0] = 0; // first time only
-        dfct(n, a, t, ip, w);
-    [parameters]
-        n              :data length - 1 (int)
-                        n >= 2, n = power of 2
-        a[0...n]       :input/output data (double *)
-                        output data
-                            a[k] = C[k], 0<=k<=n
-        t[0...n/2]     :work area (double *)
-        ip[0...*]      :work area for bit reversal (int *)
-                        length of ip >= 2+sqrt(n/4)
-                        strictly,
-                        length of ip >=
-                            2+(1<<(int)(log(n/4+0.5)/log(2))/2).
-                        ip[0],ip[1] are pointers of the cos/sin table.
-        w[0...n*5/8-1] :cos/sin table (double *)
-                        w[],ip[] are initialized if ip[0] == 0.
-    [remark]
-        Inverse of
-            a[0] *= 0.5;
-            a[n] *= 0.5;
-            dfct(n, a, t, ip, w);
-        is
-            a[0] *= 0.5;
-            a[n] *= 0.5;
-            dfct(n, a, t, ip, w);
-            for (j = 0; j <= n; j++) {
-                a[j] *= 2.0 / n;
-            }
-        .
-
-
--------- Sine Transform of RDFT (Real Anti-symmetric DFT) --------
-    [definition]
-        S[k] = sum_j=1^n-1 a[j]*sin(pi*j*k/n), 0<k<n
-    [usage]
-        ip[0] = 0; // first time only
-        dfst(n, a, t, ip, w);
-    [parameters]
-        n              :data length + 1 (int)
-                        n >= 2, n = power of 2
-        a[0...n-1]     :input/output data (double *)
-                        output data
-                            a[k] = S[k], 0<k<n
-                        (a[0] is used for work area)
-        t[0...n/2-1]   :work area (double *)
-        ip[0...*]      :work area for bit reversal (int *)
-                        length of ip >= 2+sqrt(n/4)
-                        strictly,
-                        length of ip >=
-                            2+(1<<(int)(log(n/4+0.5)/log(2))/2).
-                        ip[0],ip[1] are pointers of the cos/sin table.
-        w[0...n*5/8-1] :cos/sin table (double *)
-                        w[],ip[] are initialized if ip[0] == 0.
-    [remark]
-        Inverse of
-            dfst(n, a, t, ip, w);
-        is
-            dfst(n, a, t, ip, w);
-            for (j = 1; j <= n - 1; j++) {
-                a[j] *= 2.0 / n;
-            }
-        .
-
-
-Appendix :
-    The cos/sin table is recalculated when the larger table required.
-    w[] and ip[] are compatible with all routines.
-*/
-
-
-void cdft(int n, int isgn, double *a, int *ip, double *w)
-{
-    void makewt(int nw, int *ip, double *w);
-    void cftfsub(int n, double *a, int *ip, int nw, double *w);
-    void cftbsub(int n, double *a, int *ip, int nw, double *w);
-    int nw;
-
-    nw = ip[0];
-    if (n > (nw << 2))
-    {
-        nw = n >> 2;
-        makewt(nw, ip, w);
-    }
-    if (isgn >= 0)
-    {
-        cftfsub(n, a, ip, nw, w);
-    }
-    else
-    {
-        cftbsub(n, a, ip, nw, w);
-    }
-}
-
-
-void rdft(int n, int isgn, double *a, int *ip, double *w)
-{
-    void makewt(int nw, int *ip, double *w);
-    void makect(int nc, int *ip, double *c);
-    void cftfsub(int n, double *a, int *ip, int nw, double *w);
-    void cftbsub(int n, double *a, int *ip, int nw, double *w);
-    void rftfsub(int n, double *a, int nc, double *c);
-    void rftbsub(int n, double *a, int nc, double *c);
-    int nw, nc;
-    double xi;
-
-    nw = ip[0];
-    if (n > (nw << 2))
-    {
-        nw = n >> 2;
-        makewt(nw, ip, w);
-    }
-    nc = ip[1];
-    if (n > (nc << 2))
-    {
-        nc = n >> 2;
-        makect(nc, ip, w + nw);
-    }
-    if (isgn >= 0)
-    {
-        if (n > 4)
-        {
-            cftfsub(n, a, ip, nw, w);
-            rftfsub(n, a, nc, w + nw);
-        }
-        else if (n == 4)
-        {
-            cftfsub(n, a, ip, nw, w);
-        }
-        xi = a[0] - a[1];
-        a[0] += a[1];
-        a[1] = xi;
-    }
-    else
-    {
-        a[1] = 0.5 * (a[0] - a[1]);
-        a[0] -= a[1];
-        if (n > 4)
-        {
-            rftbsub(n, a, nc, w + nw);
-            cftbsub(n, a, ip, nw, w);
-        }
-        else if (n == 4)
-        {
-            cftbsub(n, a, ip, nw, w);
-        }
-    }
-}
-
-
-void ddct(int n, int isgn, double *a, int *ip, double *w)
-{
-    void makewt(int nw, int *ip, double *w);
-    void makect(int nc, int *ip, double *c);
-    void cftfsub(int n, double *a, int *ip, int nw, double *w);
-    void cftbsub(int n, double *a, int *ip, int nw, double *w);
-    void rftfsub(int n, double *a, int nc, double *c);
-    void rftbsub(int n, double *a, int nc, double *c);
-    void dctsub(int n, double *a, int nc, double *c);
-    int j, nw, nc;
-    double xr;
-
-    nw = ip[0];
-    if (n > (nw << 2))
-    {
-        nw = n >> 2;
-        makewt(nw, ip, w);
-    }
-    nc = ip[1];
-    if (n > nc)
-    {
-        nc = n;
-        makect(nc, ip, w + nw);
-    }
-    if (isgn < 0)
-    {
-        xr = a[n - 1];
-        for (j = n - 2; j >= 2; j -= 2)
-        {
-            a[j + 1] = a[j] - a[j - 1];
-            a[j] += a[j - 1];
-        }
-        a[1] = a[0] - xr;
-        a[0] += xr;
-        if (n > 4)
-        {
-            rftbsub(n, a, nc, w + nw);
-            cftbsub(n, a, ip, nw, w);
-        }
-        else if (n == 4)
-        {
-            cftbsub(n, a, ip, nw, w);
-        }
-    }
-    dctsub(n, a, nc, w + nw);
-    if (isgn >= 0)
-    {
-        if (n > 4)
-        {
-            cftfsub(n, a, ip, nw, w);
-            rftfsub(n, a, nc, w + nw);
-        }
-        else if (n == 4)
-        {
-            cftfsub(n, a, ip, nw, w);
-        }
-        xr = a[0] - a[1];
-        a[0] += a[1];
-        for (j = 2; j < n; j += 2)
-        {
-            a[j - 1] = a[j] - a[j + 1];
-            a[j] += a[j + 1];
-        }
-        a[n - 1] = xr;
-    }
-}
-
-
-void ddst(int n, int isgn, double *a, int *ip, double *w)
-{
-    void makewt(int nw, int *ip, double *w);
-    void makect(int nc, int *ip, double *c);
-    void cftfsub(int n, double *a, int *ip, int nw, double *w);
-    void cftbsub(int n, double *a, int *ip, int nw, double *w);
-    void rftfsub(int n, double *a, int nc, double *c);
-    void rftbsub(int n, double *a, int nc, double *c);
-    void dstsub(int n, double *a, int nc, double *c);
-    int j, nw, nc;
-    double xr;
-
-    nw = ip[0];
-    if (n > (nw << 2))
-    {
-        nw = n >> 2;
-        makewt(nw, ip, w);
-    }
-    nc = ip[1];
-    if (n > nc)
-    {
-        nc = n;
-        makect(nc, ip, w + nw);
-    }
-    if (isgn < 0)
-    {
-        xr = a[n - 1];
-        for (j = n - 2; j >= 2; j -= 2)
-        {
-            a[j + 1] = -a[j] - a[j - 1];
-            a[j] -= a[j - 1];
-        }
-        a[1] = a[0] + xr;
-        a[0] -= xr;
-        if (n > 4)
-        {
-            rftbsub(n, a, nc, w + nw);
-            cftbsub(n, a, ip, nw, w);
-        }
-        else if (n == 4)
-        {
-            cftbsub(n, a, ip, nw, w);
-        }
-    }
-    dstsub(n, a, nc, w + nw);
-    if (isgn >= 0)
-    {
-        if (n > 4)
-        {
-            cftfsub(n, a, ip, nw, w);
-            rftfsub(n, a, nc, w + nw);
-        }
-        else if (n == 4)
-        {
-            cftfsub(n, a, ip, nw, w);
-        }
-        xr = a[0] - a[1];
-        a[0] += a[1];
-        for (j = 2; j < n; j += 2)
-        {
-            a[j - 1] = -a[j] - a[j + 1];
-            a[j] -= a[j + 1];
-        }
-        a[n - 1] = -xr;
-    }
-}
-
-
-void dfct(int n, double *a, double *t, int *ip, double *w)
-{
-    void makewt(int nw, int *ip, double *w);
-    void makect(int nc, int *ip, double *c);
-    void cftfsub(int n, double *a, int *ip, int nw, double *w);
-    void rftfsub(int n, double *a, int nc, double *c);
-    void dctsub(int n, double *a, int nc, double *c);
-    int j, k, l, m, mh, nw, nc;
-    double xr, xi, yr, yi;
-
-    nw = ip[0];
-    if (n > (nw << 3))
-    {
-        nw = n >> 3;
-        makewt(nw, ip, w);
-    }
-    nc = ip[1];
-    if (n > (nc << 1))
-    {
-        nc = n >> 1;
-        makect(nc, ip, w + nw);
-    }
-    m = n >> 1;
-    yi = a[m];
-    xi = a[0] + a[n];
-    a[0] -= a[n];
-    t[0] = xi - yi;
-    t[m] = xi + yi;
-    if (n > 2)
-    {
-        mh = m >> 1;
-        for (j = 1; j < mh; j++)
-        {
-            k = m - j;
-            xr = a[j] - a[n - j];
-            xi = a[j] + a[n - j];
-            yr = a[k] - a[n - k];
-            yi = a[k] + a[n - k];
-            a[j] = xr;
-            a[k] = yr;
-            t[j] = xi - yi;
-            t[k] = xi + yi;
-        }
-        t[mh] = a[mh] + a[n - mh];
-        a[mh] -= a[n - mh];
-        dctsub(m, a, nc, w + nw);
-        if (m > 4)
-        {
-            cftfsub(m, a, ip, nw, w);
-            rftfsub(m, a, nc, w + nw);
-        }
-        else if (m == 4)
-        {
-            cftfsub(m, a, ip, nw, w);
-        }
-        a[n - 1] = a[0] - a[1];
-        a[1] = a[0] + a[1];
-        for (j = m - 2; j >= 2; j -= 2)
-        {
-            a[2 * j + 1] = a[j] + a[j + 1];
-            a[2 * j - 1] = a[j] - a[j + 1];
-        }
-        l = 2;
-        m = mh;
-        while (m >= 2)
-        {
-            dctsub(m, t, nc, w + nw);
-            if (m > 4)
-            {
-                cftfsub(m, t, ip, nw, w);
-                rftfsub(m, t, nc, w + nw);
-            }
-            else if (m == 4)
-            {
-                cftfsub(m, t, ip, nw, w);
-            }
-            a[n - l] = t[0] - t[1];
-            a[l] = t[0] + t[1];
-            k = 0;
-            for (j = 2; j < m; j += 2)
-            {
-                k += l << 2;
-                a[k - l] = t[j] - t[j + 1];
-                a[k + l] = t[j] + t[j + 1];
-            }
-            l <<= 1;
-            mh = m >> 1;
-            for (j = 0; j < mh; j++)
-            {
-                k = m - j;
-                t[j] = t[m + k] - t[m + j];
-                t[k] = t[m + k] + t[m + j];
-            }
-            t[mh] = t[m + mh];
-            m = mh;
-        }
-        a[l] = t[0];
-        a[n] = t[2] - t[1];
-        a[0] = t[2] + t[1];
-    }
-    else
-    {
-        a[1] = a[0];
-        a[2] = t[0];
-        a[0] = t[1];
-    }
-}
-
-
-void dfst(int n, double *a, double *t, int *ip, double *w)
-{
-    void makewt(int nw, int *ip, double *w);
-    void makect(int nc, int *ip, double *c);
-    void cftfsub(int n, double *a, int *ip, int nw, double *w);
-    void rftfsub(int n, double *a, int nc, double *c);
-    void dstsub(int n, double *a, int nc, double *c);
-    int j, k, l, m, mh, nw, nc;
-    double xr, xi, yr, yi;
-
-    nw = ip[0];
-    if (n > (nw << 3))
-    {
-        nw = n >> 3;
-        makewt(nw, ip, w);
-    }
-    nc = ip[1];
-    if (n > (nc << 1))
-    {
-        nc = n >> 1;
-        makect(nc, ip, w + nw);
-    }
-    if (n > 2)
-    {
-        m = n >> 1;
-        mh = m >> 1;
-        for (j = 1; j < mh; j++)
-        {
-            k = m - j;
-            xr = a[j] + a[n - j];
-            xi = a[j] - a[n - j];
-            yr = a[k] + a[n - k];
-            yi = a[k] - a[n - k];
-            a[j] = xr;
-            a[k] = yr;
-            t[j] = xi + yi;
-            t[k] = xi - yi;
-        }
-        t[0] = a[mh] - a[n - mh];
-        a[mh] += a[n - mh];
-        a[0] = a[m];
-        dstsub(m, a, nc, w + nw);
-        if (m > 4)
-        {
-            cftfsub(m, a, ip, nw, w);
-            rftfsub(m, a, nc, w + nw);
-        }
-        else if (m == 4)
-        {
-            cftfsub(m, a, ip, nw, w);
-        }
-        a[n - 1] = a[1] - a[0];
-        a[1] = a[0] + a[1];
-        for (j = m - 2; j >= 2; j -= 2)
-        {
-            a[2 * j + 1] = a[j] - a[j + 1];
-            a[2 * j - 1] = -a[j] - a[j + 1];
-        }
-        l = 2;
-        m = mh;
-        while (m >= 2)
-        {
-            dstsub(m, t, nc, w + nw);
-            if (m > 4)
-            {
-                cftfsub(m, t, ip, nw, w);
-                rftfsub(m, t, nc, w + nw);
-            }
-            else if (m == 4)
-            {
-                cftfsub(m, t, ip, nw, w);
-            }
-            a[n - l] = t[1] - t[0];
-            a[l] = t[0] + t[1];
-            k = 0;
-            for (j = 2; j < m; j += 2)
-            {
-                k += l << 2;
-                a[k - l] = -t[j] - t[j + 1];
-                a[k + l] = t[j] - t[j + 1];
-            }
-            l <<= 1;
-            mh = m >> 1;
-            for (j = 1; j < mh; j++)
-            {
-                k = m - j;
-                t[j] = t[m + k] + t[m + j];
-                t[k] = t[m + k] - t[m + j];
-            }
-            t[0] = t[m + mh];
-            m = mh;
-        }
-        a[l] = t[0];
-    }
-    a[0] = 0;
-}
-
-
-/* -------- initializing routines -------- */
-
-
-#include <math.h>
-
-void makewt(int nw, int *ip, double *w)
-{
-    void makeipt(int nw, int *ip);
-    int j, nwh, nw0, nw1;
-    double delta, wn4r, wk1r, wk1i, wk3r, wk3i;
-
-    ip[0] = nw;
-    ip[1] = 1;
-    if (nw > 2)
-    {
-        nwh = nw >> 1;
-        delta = atan(1.0) / nwh;
-        wn4r = cos(delta * nwh);
-        w[0] = 1;
-        w[1] = wn4r;
-        if (nwh == 4)
-        {
-            w[2] = cos(delta * 2);
-            w[3] = sin(delta * 2);
-        }
-        else if (nwh > 4)
-        {
-            makeipt(nw, ip);
-            w[2] = 0.5 / cos(delta * 2);
-            w[3] = 0.5 / cos(delta * 6);
-            for (j = 4; j < nwh; j += 4)
-            {
-                w[j] = cos(delta * j);
-                w[j + 1] = sin(delta * j);
-                w[j + 2] = cos(3 * delta * j);
-                w[j + 3] = -sin(3 * delta * j);
-            }
-        }
-        nw0 = 0;
-        while (nwh > 2)
-        {
-            nw1 = nw0 + nwh;
-            nwh >>= 1;
-            w[nw1] = 1;
-            w[nw1 + 1] = wn4r;
-            if (nwh == 4)
-            {
-                wk1r = w[nw0 + 4];
-                wk1i = w[nw0 + 5];
-                w[nw1 + 2] = wk1r;
-                w[nw1 + 3] = wk1i;
-            }
-            else if (nwh > 4)
-            {
-                wk1r = w[nw0 + 4];
-                wk3r = w[nw0 + 6];
-                w[nw1 + 2] = 0.5 / wk1r;
-                w[nw1 + 3] = 0.5 / wk3r;
-                for (j = 4; j < nwh; j += 4)
-                {
-                    wk1r = w[nw0 + 2 * j];
-                    wk1i = w[nw0 + 2 * j + 1];
-                    wk3r = w[nw0 + 2 * j + 2];
-                    wk3i = w[nw0 + 2 * j + 3];
-                    w[nw1 + j] = wk1r;
-                    w[nw1 + j + 1] = wk1i;
-                    w[nw1 + j + 2] = wk3r;
-                    w[nw1 + j + 3] = wk3i;
-                }
-            }
-            nw0 = nw1;
-        }
-    }
-}
-
-
-void makeipt(int nw, int *ip)
-{
-    int j, l, m, m2, p, q;
-
-    ip[2] = 0;
-    ip[3] = 16;
-    m = 2;
-    for (l = nw; l > 32; l >>= 2)
-    {
-        m2 = m << 1;
-        q = m2 << 3;
-        for (j = m; j < m2; j++)
-        {
-            p = ip[j] << 2;
-            ip[m + j] = p;
-            ip[m2 + j] = p + q;
-        }
-        m = m2;
-    }
-}
-
-
-void makect(int nc, int *ip, double *c)
-{
-    int j, nch;
-    double delta;
-
-    ip[1] = nc;
-    if (nc > 1)
-    {
-        nch = nc >> 1;
-        delta = atan(1.0) / nch;
-        c[0] = cos(delta * nch);
-        c[nch] = 0.5 * c[0];
-        for (j = 1; j < nch; j++)
-        {
-            c[j] = 0.5 * cos(delta * j);
-            c[nc - j] = 0.5 * sin(delta * j);
-        }
-    }
-}
-
-
-/* -------- child routines -------- */
-
-
-#ifdef USE_CDFT_PTHREADS
-#define USE_CDFT_THREADS
-#ifndef CDFT_THREADS_BEGIN_N
-#define CDFT_THREADS_BEGIN_N 8192
-#endif
-#ifndef CDFT_4THREADS_BEGIN_N
-#define CDFT_4THREADS_BEGIN_N 65536
-#endif
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#define cdft_thread_t pthread_t
-#define cdft_thread_create(thp,func,argp) { \
-    if (pthread_create(thp, NULL, func, (void *) argp) != 0) { \
-        fprintf(stderr, "cdft thread error\n"); \
-        exit(1); \
-    } \
-}
-#define cdft_thread_wait(th) { \
-    if (pthread_join(th, NULL) != 0) { \
-        fprintf(stderr, "cdft thread error\n"); \
-        exit(1); \
-    } \
-}
-#endif /* USE_CDFT_PTHREADS */
-
-
-#ifdef USE_CDFT_WINTHREADS
-#define USE_CDFT_THREADS
-#ifndef CDFT_THREADS_BEGIN_N
-#define CDFT_THREADS_BEGIN_N 32768
-#endif
-#ifndef CDFT_4THREADS_BEGIN_N
-#define CDFT_4THREADS_BEGIN_N 524288
-#endif
-#include <windows.h>
-#include <stdio.h>
-#include <stdlib.h>
-#define cdft_thread_t HANDLE
-#define cdft_thread_create(thp,func,argp) { \
-    DWORD thid; \
-    *(thp) = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) func, (LPVOID) argp, 0, &thid); \
-    if (*(thp) == 0) { \
-        fprintf(stderr, "cdft thread error\n"); \
-        exit(1); \
-    } \
-}
-#define cdft_thread_wait(th) { \
-    WaitForSingleObject(th, INFINITE); \
-    CloseHandle(th); \
-}
-#endif /* USE_CDFT_WINTHREADS */
-
-
-void cftfsub(int n, double *a, int *ip, int nw, double *w)
-{
-    void bitrv2(int n, int *ip, double *a);
-    void bitrv216(double *a);
-    void bitrv208(double *a);
-    void cftf1st(int n, double *a, double *w);
-    void cftrec4(int n, double *a, int nw, double *w);
-    void cftleaf(int n, int isplt, double *a, int nw, double *w);
-    void cftfx41(int n, double *a, int nw, double *w);
-    void cftf161(double *a, double *w);
-    void cftf081(double *a, double *w);
-    void cftf040(double *a);
-    void cftx020(double *a);
-#ifdef USE_CDFT_THREADS
-    void cftrec4_th(int n, double *a, int nw, double *w);
-#endif /* USE_CDFT_THREADS */
-
-    if (n > 8)
-    {
-        if (n > 32)
-        {
-            cftf1st(n, a, &w[nw - (n >> 2)]);
-#ifdef USE_CDFT_THREADS
-            if (n > CDFT_THREADS_BEGIN_N)
-            {
-                cftrec4_th(n, a, nw, w);
-            }
-            else
-#endif /* USE_CDFT_THREADS */
-                if (n > 512)
-                {
-                    cftrec4(n, a, nw, w);
-                }
-                else if (n > 128)
-                {
-                    cftleaf(n, 1, a, nw, w);
-                }
-                else
-                {
-                    cftfx41(n, a, nw, w);
-                }
-            bitrv2(n, ip, a);
-        }
-        else if (n == 32)
-        {
-            cftf161(a, &w[nw - 8]);
-            bitrv216(a);
-        }
-        else
-        {
-            cftf081(a, w);
-            bitrv208(a);
-        }
-    }
-    else if (n == 8)
-    {
-        cftf040(a);
-    }
-    else if (n == 4)
-    {
-        cftx020(a);
-    }
-}
-
-
-void cftbsub(int n, double *a, int *ip, int nw, double *w)
-{
-    void bitrv2conj(int n, int *ip, double *a);
-    void bitrv216neg(double *a);
-    void bitrv208neg(double *a);
-    void cftb1st(int n, double *a, double *w);
-    void cftrec4(int n, double *a, int nw, double *w);
-    void cftleaf(int n, int isplt, double *a, int nw, double *w);
-    void cftfx41(int n, double *a, int nw, double *w);
-    void cftf161(double *a, double *w);
-    void cftf081(double *a, double *w);
-    void cftb040(double *a);
-    void cftx020(double *a);
-#ifdef USE_CDFT_THREADS
-    void cftrec4_th(int n, double *a, int nw, double *w);
-#endif /* USE_CDFT_THREADS */
-
-    if (n > 8)
-    {
-        if (n > 32)
-        {
-            cftb1st(n, a, &w[nw - (n >> 2)]);
-#ifdef USE_CDFT_THREADS
-            if (n > CDFT_THREADS_BEGIN_N)
-            {
-                cftrec4_th(n, a, nw, w);
-            }
-            else
-#endif /* USE_CDFT_THREADS */
-                if (n > 512)
-                {
-                    cftrec4(n, a, nw, w);
-                }
-                else if (n > 128)
-                {
-                    cftleaf(n, 1, a, nw, w);
-                }
-                else
-                {
-                    cftfx41(n, a, nw, w);
-                }
-            bitrv2conj(n, ip, a);
-        }
-        else if (n == 32)
-        {
-            cftf161(a, &w[nw - 8]);
-            bitrv216neg(a);
-        }
-        else
-        {
-            cftf081(a, w);
-            bitrv208neg(a);
-        }
-    }
-    else if (n == 8)
-    {
-        cftb040(a);
-    }
-    else if (n == 4)
-    {
-        cftx020(a);
-    }
-}
-
-
-void bitrv2(int n, int *ip, double *a)
-{
-    int j, j1, k, k1, l, m, nh, nm;
-    double xr, xi, yr, yi;
-
-    m = 1;
-    for (l = n >> 2; l > 8; l >>= 2)
-    {
-        m <<= 1;
-    }
-    nh = n >> 1;
-    nm = 4 * m;
-    if (l == 8)
-    {
-        for (k = 0; k < m; k++)
-        {
-            for (j = 0; j < k; j++)
-            {
-                j1 = 4 * j + 2 * ip[m + k];
-                k1 = 4 * k + 2 * ip[m + j];
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nh;
-                k1 += 2;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += 2;
-                k1 += nh;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nh;
-                k1 -= 2;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-            }
-            k1 = 4 * k + 2 * ip[m + k];
-            j1 = k1 + 2;
-            k1 += nh;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 += nm;
-            k1 += 2 * nm;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 += nm;
-            k1 -= nm;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 -= 2;
-            k1 -= nh;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 += nh + 2;
-            k1 += nh + 2;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 -= nh - nm;
-            k1 += 2 * nm - 2;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-        }
-    }
-    else
-    {
-        for (k = 0; k < m; k++)
-        {
-            for (j = 0; j < k; j++)
-            {
-                j1 = 4 * j + ip[m + k];
-                k1 = 4 * k + ip[m + j];
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nh;
-                k1 += 2;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += 2;
-                k1 += nh;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nh;
-                k1 -= 2;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = a[j1 + 1];
-                yr = a[k1];
-                yi = a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-            }
-            k1 = 4 * k + ip[m + k];
-            j1 = k1 + 2;
-            k1 += nh;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 += nm;
-            k1 += nm;
-            xr = a[j1];
-            xi = a[j1 + 1];
-            yr = a[k1];
-            yi = a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-        }
-    }
-}
-
-
-void bitrv2conj(int n, int *ip, double *a)
-{
-    int j, j1, k, k1, l, m, nh, nm;
-    double xr, xi, yr, yi;
-
-    m = 1;
-    for (l = n >> 2; l > 8; l >>= 2)
-    {
-        m <<= 1;
-    }
-    nh = n >> 1;
-    nm = 4 * m;
-    if (l == 8)
-    {
-        for (k = 0; k < m; k++)
-        {
-            for (j = 0; j < k; j++)
-            {
-                j1 = 4 * j + 2 * ip[m + k];
-                k1 = 4 * k + 2 * ip[m + j];
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nh;
-                k1 += 2;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += 2;
-                k1 += nh;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nh;
-                k1 -= 2;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= 2 * nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-            }
-            k1 = 4 * k + 2 * ip[m + k];
-            j1 = k1 + 2;
-            k1 += nh;
-            a[j1 - 1] = -a[j1 - 1];
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            a[k1 + 3] = -a[k1 + 3];
-            j1 += nm;
-            k1 += 2 * nm;
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 += nm;
-            k1 -= nm;
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 -= 2;
-            k1 -= nh;
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 += nh + 2;
-            k1 += nh + 2;
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            j1 -= nh - nm;
-            k1 += 2 * nm - 2;
-            a[j1 - 1] = -a[j1 - 1];
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            a[k1 + 3] = -a[k1 + 3];
-        }
-    }
-    else
-    {
-        for (k = 0; k < m; k++)
-        {
-            for (j = 0; j < k; j++)
-            {
-                j1 = 4 * j + ip[m + k];
-                k1 = 4 * k + ip[m + j];
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nh;
-                k1 += 2;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += 2;
-                k1 += nh;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 += nm;
-                k1 += nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nh;
-                k1 -= 2;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-                j1 -= nm;
-                k1 -= nm;
-                xr = a[j1];
-                xi = -a[j1 + 1];
-                yr = a[k1];
-                yi = -a[k1 + 1];
-                a[j1] = yr;
-                a[j1 + 1] = yi;
-                a[k1] = xr;
-                a[k1 + 1] = xi;
-            }
-            k1 = 4 * k + ip[m + k];
-            j1 = k1 + 2;
-            k1 += nh;
-            a[j1 - 1] = -a[j1 - 1];
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            a[k1 + 3] = -a[k1 + 3];
-            j1 += nm;
-            k1 += nm;
-            a[j1 - 1] = -a[j1 - 1];
-            xr = a[j1];
-            xi = -a[j1 + 1];
-            yr = a[k1];
-            yi = -a[k1 + 1];
-            a[j1] = yr;
-            a[j1 + 1] = yi;
-            a[k1] = xr;
-            a[k1 + 1] = xi;
-            a[k1 + 3] = -a[k1 + 3];
-        }
-    }
-}
-
-
-void bitrv216(double *a)
-{
-    double x1r, x1i, x2r, x2i, x3r, x3i, x4r, x4i,
-           x5r, x5i, x7r, x7i, x8r, x8i, x10r, x10i,
-           x11r, x11i, x12r, x12i, x13r, x13i, x14r, x14i;
-
-    x1r = a[2];
-    x1i = a[3];
-    x2r = a[4];
-    x2i = a[5];
-    x3r = a[6];
-    x3i = a[7];
-    x4r = a[8];
-    x4i = a[9];
-    x5r = a[10];
-    x5i = a[11];
-    x7r = a[14];
-    x7i = a[15];
-    x8r = a[16];
-    x8i = a[17];
-    x10r = a[20];
-    x10i = a[21];
-    x11r = a[22];
-    x11i = a[23];
-    x12r = a[24];
-    x12i = a[25];
-    x13r = a[26];
-    x13i = a[27];
-    x14r = a[28];
-    x14i = a[29];
-    a[2] = x8r;
-    a[3] = x8i;
-    a[4] = x4r;
-    a[5] = x4i;
-    a[6] = x12r;
-    a[7] = x12i;
-    a[8] = x2r;
-    a[9] = x2i;
-    a[10] = x10r;
-    a[11] = x10i;
-    a[14] = x14r;
-    a[15] = x14i;
-    a[16] = x1r;
-    a[17] = x1i;
-    a[20] = x5r;
-    a[21] = x5i;
-    a[22] = x13r;
-    a[23] = x13i;
-    a[24] = x3r;
-    a[25] = x3i;
-    a[26] = x11r;
-    a[27] = x11i;
-    a[28] = x7r;
-    a[29] = x7i;
-}
-
-
-void bitrv216neg(double *a)
-{
-    double x1r, x1i, x2r, x2i, x3r, x3i, x4r, x4i,
-           x5r, x5i, x6r, x6i, x7r, x7i, x8r, x8i,
-           x9r, x9i, x10r, x10i, x11r, x11i, x12r, x12i,
-           x13r, x13i, x14r, x14i, x15r, x15i;
-
-    x1r = a[2];
-    x1i = a[3];
-    x2r = a[4];
-    x2i = a[5];
-    x3r = a[6];
-    x3i = a[7];
-    x4r = a[8];
-    x4i = a[9];
-    x5r = a[10];
-    x5i = a[11];
-    x6r = a[12];
-    x6i = a[13];
-    x7r = a[14];
-    x7i = a[15];
-    x8r = a[16];
-    x8i = a[17];
-    x9r = a[18];
-    x9i = a[19];
-    x10r = a[20];
-    x10i = a[21];
-    x11r = a[22];
-    x11i = a[23];
-    x12r = a[24];
-    x12i = a[25];
-    x13r = a[26];
-    x13i = a[27];
-    x14r = a[28];
-    x14i = a[29];
-    x15r = a[30];
-    x15i = a[31];
-    a[2] = x15r;
-    a[3] = x15i;
-    a[4] = x7r;
-    a[5] = x7i;
-    a[6] = x11r;
-    a[7] = x11i;
-    a[8] = x3r;
-    a[9] = x3i;
-    a[10] = x13r;
-    a[11] = x13i;
-    a[12] = x5r;
-    a[13] = x5i;
-    a[14] = x9r;
-    a[15] = x9i;
-    a[16] = x1r;
-    a[17] = x1i;
-    a[18] = x14r;
-    a[19] = x14i;
-    a[20] = x6r;
-    a[21] = x6i;
-    a[22] = x10r;
-    a[23] = x10i;
-    a[24] = x2r;
-    a[25] = x2i;
-    a[26] = x12r;
-    a[27] = x12i;
-    a[28] = x4r;
-    a[29] = x4i;
-    a[30] = x8r;
-    a[31] = x8i;
-}
-
-
-void bitrv208(double *a)
-{
-    double x1r, x1i, x3r, x3i, x4r, x4i, x6r, x6i;
-
-    x1r = a[2];
-    x1i = a[3];
-    x3r = a[6];
-    x3i = a[7];
-    x4r = a[8];
-    x4i = a[9];
-    x6r = a[12];
-    x6i = a[13];
-    a[2] = x4r;
-    a[3] = x4i;
-    a[6] = x6r;
-    a[7] = x6i;
-    a[8] = x1r;
-    a[9] = x1i;
-    a[12] = x3r;
-    a[13] = x3i;
-}
-
-
-void bitrv208neg(double *a)
-{
-    double x1r, x1i, x2r, x2i, x3r, x3i, x4r, x4i,
-           x5r, x5i, x6r, x6i, x7r, x7i;
-
-    x1r = a[2];
-    x1i = a[3];
-    x2r = a[4];
-    x2i = a[5];
-    x3r = a[6];
-    x3i = a[7];
-    x4r = a[8];
-    x4i = a[9];
-    x5r = a[10];
-    x5i = a[11];
-    x6r = a[12];
-    x6i = a[13];
-    x7r = a[14];
-    x7i = a[15];
-    a[2] = x7r;
-    a[3] = x7i;
-    a[4] = x3r;
-    a[5] = x3i;
-    a[6] = x5r;
-    a[7] = x5i;
-    a[8] = x1r;
-    a[9] = x1i;
-    a[10] = x6r;
-    a[11] = x6i;
-    a[12] = x2r;
-    a[13] = x2i;
-    a[14] = x4r;
-    a[15] = x4i;
-}
-
-
-void cftf1st(int n, double *a, double *w)
-{
-    int j, j0, j1, j2, j3, k, m, mh;
-    double wn4r, csc1, csc3, wk1r, wk1i, wk3r, wk3i,
-           wd1r, wd1i, wd3r, wd3i;
-    double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i,
-           y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i;
-
-    mh = n >> 3;
-    m = 2 * mh;
-    j1 = m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[0] + a[j2];
-    x0i = a[1] + a[j2 + 1];
-    x1r = a[0] - a[j2];
-    x1i = a[1] - a[j2 + 1];
-    x2r = a[j1] + a[j3];
-    x2i = a[j1 + 1] + a[j3 + 1];
-    x3r = a[j1] - a[j3];
-    x3i = a[j1 + 1] - a[j3 + 1];
-    a[0] = x0r + x2r;
-    a[1] = x0i + x2i;
-    a[j1] = x0r - x2r;
-    a[j1 + 1] = x0i - x2i;
-    a[j2] = x1r - x3i;
-    a[j2 + 1] = x1i + x3r;
-    a[j3] = x1r + x3i;
-    a[j3 + 1] = x1i - x3r;
-    wn4r = w[1];
-    csc1 = w[2];
-    csc3 = w[3];
-    wd1r = 1;
-    wd1i = 0;
-    wd3r = 1;
-    wd3i = 0;
-    k = 0;
-    for (j = 2; j < mh - 2; j += 4)
-    {
-        k += 4;
-        wk1r = csc1 * (wd1r + w[k]);
-        wk1i = csc1 * (wd1i + w[k + 1]);
-        wk3r = csc3 * (wd3r + w[k + 2]);
-        wk3i = csc3 * (wd3i + w[k + 3]);
-        wd1r = w[k];
-        wd1i = w[k + 1];
-        wd3r = w[k + 2];
-        wd3i = w[k + 3];
-        j1 = j + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j] + a[j2];
-        x0i = a[j + 1] + a[j2 + 1];
-        x1r = a[j] - a[j2];
-        x1i = a[j + 1] - a[j2 + 1];
-        y0r = a[j + 2] + a[j2 + 2];
-        y0i = a[j + 3] + a[j2 + 3];
-        y1r = a[j + 2] - a[j2 + 2];
-        y1i = a[j + 3] - a[j2 + 3];
-        x2r = a[j1] + a[j3];
-        x2i = a[j1 + 1] + a[j3 + 1];
-        x3r = a[j1] - a[j3];
-        x3i = a[j1 + 1] - a[j3 + 1];
-        y2r = a[j1 + 2] + a[j3 + 2];
-        y2i = a[j1 + 3] + a[j3 + 3];
-        y3r = a[j1 + 2] - a[j3 + 2];
-        y3i = a[j1 + 3] - a[j3 + 3];
-        a[j] = x0r + x2r;
-        a[j + 1] = x0i + x2i;
-        a[j + 2] = y0r + y2r;
-        a[j + 3] = y0i + y2i;
-        a[j1] = x0r - x2r;
-        a[j1 + 1] = x0i - x2i;
-        a[j1 + 2] = y0r - y2r;
-        a[j1 + 3] = y0i - y2i;
-        x0r = x1r - x3i;
-        x0i = x1i + x3r;
-        a[j2] = wk1r * x0r - wk1i * x0i;
-        a[j2 + 1] = wk1r * x0i + wk1i * x0r;
-        x0r = y1r - y3i;
-        x0i = y1i + y3r;
-        a[j2 + 2] = wd1r * x0r - wd1i * x0i;
-        a[j2 + 3] = wd1r * x0i + wd1i * x0r;
-        x0r = x1r + x3i;
-        x0i = x1i - x3r;
-        a[j3] = wk3r * x0r + wk3i * x0i;
-        a[j3 + 1] = wk3r * x0i - wk3i * x0r;
-        x0r = y1r + y3i;
-        x0i = y1i - y3r;
-        a[j3 + 2] = wd3r * x0r + wd3i * x0i;
-        a[j3 + 3] = wd3r * x0i - wd3i * x0r;
-        j0 = m - j;
-        j1 = j0 + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j0] + a[j2];
-        x0i = a[j0 + 1] + a[j2 + 1];
-        x1r = a[j0] - a[j2];
-        x1i = a[j0 + 1] - a[j2 + 1];
-        y0r = a[j0 - 2] + a[j2 - 2];
-        y0i = a[j0 - 1] + a[j2 - 1];
-        y1r = a[j0 - 2] - a[j2 - 2];
-        y1i = a[j0 - 1] - a[j2 - 1];
-        x2r = a[j1] + a[j3];
-        x2i = a[j1 + 1] + a[j3 + 1];
-        x3r = a[j1] - a[j3];
-        x3i = a[j1 + 1] - a[j3 + 1];
-        y2r = a[j1 - 2] + a[j3 - 2];
-        y2i = a[j1 - 1] + a[j3 - 1];
-        y3r = a[j1 - 2] - a[j3 - 2];
-        y3i = a[j1 - 1] - a[j3 - 1];
-        a[j0] = x0r + x2r;
-        a[j0 + 1] = x0i + x2i;
-        a[j0 - 2] = y0r + y2r;
-        a[j0 - 1] = y0i + y2i;
-        a[j1] = x0r - x2r;
-        a[j1 + 1] = x0i - x2i;
-        a[j1 - 2] = y0r - y2r;
-        a[j1 - 1] = y0i - y2i;
-        x0r = x1r - x3i;
-        x0i = x1i + x3r;
-        a[j2] = wk1i * x0r - wk1r * x0i;
-        a[j2 + 1] = wk1i * x0i + wk1r * x0r;
-        x0r = y1r - y3i;
-        x0i = y1i + y3r;
-        a[j2 - 2] = wd1i * x0r - wd1r * x0i;
-        a[j2 - 1] = wd1i * x0i + wd1r * x0r;
-        x0r = x1r + x3i;
-        x0i = x1i - x3r;
-        a[j3] = wk3i * x0r + wk3r * x0i;
-        a[j3 + 1] = wk3i * x0i - wk3r * x0r;
-        x0r = y1r + y3i;
-        x0i = y1i - y3r;
-        a[j3 - 2] = wd3i * x0r + wd3r * x0i;
-        a[j3 - 1] = wd3i * x0i - wd3r * x0r;
-    }
-    wk1r = csc1 * (wd1r + wn4r);
-    wk1i = csc1 * (wd1i + wn4r);
-    wk3r = csc3 * (wd3r - wn4r);
-    wk3i = csc3 * (wd3i - wn4r);
-    j0 = mh;
-    j1 = j0 + m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[j0 - 2] + a[j2 - 2];
-    x0i = a[j0 - 1] + a[j2 - 1];
-    x1r = a[j0 - 2] - a[j2 - 2];
-    x1i = a[j0 - 1] - a[j2 - 1];
-    x2r = a[j1 - 2] + a[j3 - 2];
-    x2i = a[j1 - 1] + a[j3 - 1];
-    x3r = a[j1 - 2] - a[j3 - 2];
-    x3i = a[j1 - 1] - a[j3 - 1];
-    a[j0 - 2] = x0r + x2r;
-    a[j0 - 1] = x0i + x2i;
-    a[j1 - 2] = x0r - x2r;
-    a[j1 - 1] = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    a[j2 - 2] = wk1r * x0r - wk1i * x0i;
-    a[j2 - 1] = wk1r * x0i + wk1i * x0r;
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    a[j3 - 2] = wk3r * x0r + wk3i * x0i;
-    a[j3 - 1] = wk3r * x0i - wk3i * x0r;
-    x0r = a[j0] + a[j2];
-    x0i = a[j0 + 1] + a[j2 + 1];
-    x1r = a[j0] - a[j2];
-    x1i = a[j0 + 1] - a[j2 + 1];
-    x2r = a[j1] + a[j3];
-    x2i = a[j1 + 1] + a[j3 + 1];
-    x3r = a[j1] - a[j3];
-    x3i = a[j1 + 1] - a[j3 + 1];
-    a[j0] = x0r + x2r;
-    a[j0 + 1] = x0i + x2i;
-    a[j1] = x0r - x2r;
-    a[j1 + 1] = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    a[j2] = wn4r * (x0r - x0i);
-    a[j2 + 1] = wn4r * (x0i + x0r);
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    a[j3] = -wn4r * (x0r + x0i);
-    a[j3 + 1] = -wn4r * (x0i - x0r);
-    x0r = a[j0 + 2] + a[j2 + 2];
-    x0i = a[j0 + 3] + a[j2 + 3];
-    x1r = a[j0 + 2] - a[j2 + 2];
-    x1i = a[j0 + 3] - a[j2 + 3];
-    x2r = a[j1 + 2] + a[j3 + 2];
-    x2i = a[j1 + 3] + a[j3 + 3];
-    x3r = a[j1 + 2] - a[j3 + 2];
-    x3i = a[j1 + 3] - a[j3 + 3];
-    a[j0 + 2] = x0r + x2r;
-    a[j0 + 3] = x0i + x2i;
-    a[j1 + 2] = x0r - x2r;
-    a[j1 + 3] = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    a[j2 + 2] = wk1i * x0r - wk1r * x0i;
-    a[j2 + 3] = wk1i * x0i + wk1r * x0r;
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    a[j3 + 2] = wk3i * x0r + wk3r * x0i;
-    a[j3 + 3] = wk3i * x0i - wk3r * x0r;
-}
-
-
-void cftb1st(int n, double *a, double *w)
-{
-    int j, j0, j1, j2, j3, k, m, mh;
-    double wn4r, csc1, csc3, wk1r, wk1i, wk3r, wk3i,
-           wd1r, wd1i, wd3r, wd3i;
-    double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i,
-           y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i;
-
-    mh = n >> 3;
-    m = 2 * mh;
-    j1 = m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[0] + a[j2];
-    x0i = -a[1] - a[j2 + 1];
-    x1r = a[0] - a[j2];
-    x1i = -a[1] + a[j2 + 1];
-    x2r = a[j1] + a[j3];
-    x2i = a[j1 + 1] + a[j3 + 1];
-    x3r = a[j1] - a[j3];
-    x3i = a[j1 + 1] - a[j3 + 1];
-    a[0] = x0r + x2r;
-    a[1] = x0i - x2i;
-    a[j1] = x0r - x2r;
-    a[j1 + 1] = x0i + x2i;
-    a[j2] = x1r + x3i;
-    a[j2 + 1] = x1i + x3r;
-    a[j3] = x1r - x3i;
-    a[j3 + 1] = x1i - x3r;
-    wn4r = w[1];
-    csc1 = w[2];
-    csc3 = w[3];
-    wd1r = 1;
-    wd1i = 0;
-    wd3r = 1;
-    wd3i = 0;
-    k = 0;
-    for (j = 2; j < mh - 2; j += 4)
-    {
-        k += 4;
-        wk1r = csc1 * (wd1r + w[k]);
-        wk1i = csc1 * (wd1i + w[k + 1]);
-        wk3r = csc3 * (wd3r + w[k + 2]);
-        wk3i = csc3 * (wd3i + w[k + 3]);
-        wd1r = w[k];
-        wd1i = w[k + 1];
-        wd3r = w[k + 2];
-        wd3i = w[k + 3];
-        j1 = j + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j] + a[j2];
-        x0i = -a[j + 1] - a[j2 + 1];
-        x1r = a[j] - a[j2];
-        x1i = -a[j + 1] + a[j2 + 1];
-        y0r = a[j + 2] + a[j2 + 2];
-        y0i = -a[j + 3] - a[j2 + 3];
-        y1r = a[j + 2] - a[j2 + 2];
-        y1i = -a[j + 3] + a[j2 + 3];
-        x2r = a[j1] + a[j3];
-        x2i = a[j1 + 1] + a[j3 + 1];
-        x3r = a[j1] - a[j3];
-        x3i = a[j1 + 1] - a[j3 + 1];
-        y2r = a[j1 + 2] + a[j3 + 2];
-        y2i = a[j1 + 3] + a[j3 + 3];
-        y3r = a[j1 + 2] - a[j3 + 2];
-        y3i = a[j1 + 3] - a[j3 + 3];
-        a[j] = x0r + x2r;
-        a[j + 1] = x0i - x2i;
-        a[j + 2] = y0r + y2r;
-        a[j + 3] = y0i - y2i;
-        a[j1] = x0r - x2r;
-        a[j1 + 1] = x0i + x2i;
-        a[j1 + 2] = y0r - y2r;
-        a[j1 + 3] = y0i + y2i;
-        x0r = x1r + x3i;
-        x0i = x1i + x3r;
-        a[j2] = wk1r * x0r - wk1i * x0i;
-        a[j2 + 1] = wk1r * x0i + wk1i * x0r;
-        x0r = y1r + y3i;
-        x0i = y1i + y3r;
-        a[j2 + 2] = wd1r * x0r - wd1i * x0i;
-        a[j2 + 3] = wd1r * x0i + wd1i * x0r;
-        x0r = x1r - x3i;
-        x0i = x1i - x3r;
-        a[j3] = wk3r * x0r + wk3i * x0i;
-        a[j3 + 1] = wk3r * x0i - wk3i * x0r;
-        x0r = y1r - y3i;
-        x0i = y1i - y3r;
-        a[j3 + 2] = wd3r * x0r + wd3i * x0i;
-        a[j3 + 3] = wd3r * x0i - wd3i * x0r;
-        j0 = m - j;
-        j1 = j0 + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j0] + a[j2];
-        x0i = -a[j0 + 1] - a[j2 + 1];
-        x1r = a[j0] - a[j2];
-        x1i = -a[j0 + 1] + a[j2 + 1];
-        y0r = a[j0 - 2] + a[j2 - 2];
-        y0i = -a[j0 - 1] - a[j2 - 1];
-        y1r = a[j0 - 2] - a[j2 - 2];
-        y1i = -a[j0 - 1] + a[j2 - 1];
-        x2r = a[j1] + a[j3];
-        x2i = a[j1 + 1] + a[j3 + 1];
-        x3r = a[j1] - a[j3];
-        x3i = a[j1 + 1] - a[j3 + 1];
-        y2r = a[j1 - 2] + a[j3 - 2];
-        y2i = a[j1 - 1] + a[j3 - 1];
-        y3r = a[j1 - 2] - a[j3 - 2];
-        y3i = a[j1 - 1] - a[j3 - 1];
-        a[j0] = x0r + x2r;
-        a[j0 + 1] = x0i - x2i;
-        a[j0 - 2] = y0r + y2r;
-        a[j0 - 1] = y0i - y2i;
-        a[j1] = x0r - x2r;
-        a[j1 + 1] = x0i + x2i;
-        a[j1 - 2] = y0r - y2r;
-        a[j1 - 1] = y0i + y2i;
-        x0r = x1r + x3i;
-        x0i = x1i + x3r;
-        a[j2] = wk1i * x0r - wk1r * x0i;
-        a[j2 + 1] = wk1i * x0i + wk1r * x0r;
-        x0r = y1r + y3i;
-        x0i = y1i + y3r;
-        a[j2 - 2] = wd1i * x0r - wd1r * x0i;
-        a[j2 - 1] = wd1i * x0i + wd1r * x0r;
-        x0r = x1r - x3i;
-        x0i = x1i - x3r;
-        a[j3] = wk3i * x0r + wk3r * x0i;
-        a[j3 + 1] = wk3i * x0i - wk3r * x0r;
-        x0r = y1r - y3i;
-        x0i = y1i - y3r;
-        a[j3 - 2] = wd3i * x0r + wd3r * x0i;
-        a[j3 - 1] = wd3i * x0i - wd3r * x0r;
-    }
-    wk1r = csc1 * (wd1r + wn4r);
-    wk1i = csc1 * (wd1i + wn4r);
-    wk3r = csc3 * (wd3r - wn4r);
-    wk3i = csc3 * (wd3i - wn4r);
-    j0 = mh;
-    j1 = j0 + m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[j0 - 2] + a[j2 - 2];
-    x0i = -a[j0 - 1] - a[j2 - 1];
-    x1r = a[j0 - 2] - a[j2 - 2];
-    x1i = -a[j0 - 1] + a[j2 - 1];
-    x2r = a[j1 - 2] + a[j3 - 2];
-    x2i = a[j1 - 1] + a[j3 - 1];
-    x3r = a[j1 - 2] - a[j3 - 2];
-    x3i = a[j1 - 1] - a[j3 - 1];
-    a[j0 - 2] = x0r + x2r;
-    a[j0 - 1] = x0i - x2i;
-    a[j1 - 2] = x0r - x2r;
-    a[j1 - 1] = x0i + x2i;
-    x0r = x1r + x3i;
-    x0i = x1i + x3r;
-    a[j2 - 2] = wk1r * x0r - wk1i * x0i;
-    a[j2 - 1] = wk1r * x0i + wk1i * x0r;
-    x0r = x1r - x3i;
-    x0i = x1i - x3r;
-    a[j3 - 2] = wk3r * x0r + wk3i * x0i;
-    a[j3 - 1] = wk3r * x0i - wk3i * x0r;
-    x0r = a[j0] + a[j2];
-    x0i = -a[j0 + 1] - a[j2 + 1];
-    x1r = a[j0] - a[j2];
-    x1i = -a[j0 + 1] + a[j2 + 1];
-    x2r = a[j1] + a[j3];
-    x2i = a[j1 + 1] + a[j3 + 1];
-    x3r = a[j1] - a[j3];
-    x3i = a[j1 + 1] - a[j3 + 1];
-    a[j0] = x0r + x2r;
-    a[j0 + 1] = x0i - x2i;
-    a[j1] = x0r - x2r;
-    a[j1 + 1] = x0i + x2i;
-    x0r = x1r + x3i;
-    x0i = x1i + x3r;
-    a[j2] = wn4r * (x0r - x0i);
-    a[j2 + 1] = wn4r * (x0i + x0r);
-    x0r = x1r - x3i;
-    x0i = x1i - x3r;
-    a[j3] = -wn4r * (x0r + x0i);
-    a[j3 + 1] = -wn4r * (x0i - x0r);
-    x0r = a[j0 + 2] + a[j2 + 2];
-    x0i = -a[j0 + 3] - a[j2 + 3];
-    x1r = a[j0 + 2] - a[j2 + 2];
-    x1i = -a[j0 + 3] + a[j2 + 3];
-    x2r = a[j1 + 2] + a[j3 + 2];
-    x2i = a[j1 + 3] + a[j3 + 3];
-    x3r = a[j1 + 2] - a[j3 + 2];
-    x3i = a[j1 + 3] - a[j3 + 3];
-    a[j0 + 2] = x0r + x2r;
-    a[j0 + 3] = x0i - x2i;
-    a[j1 + 2] = x0r - x2r;
-    a[j1 + 3] = x0i + x2i;
-    x0r = x1r + x3i;
-    x0i = x1i + x3r;
-    a[j2 + 2] = wk1i * x0r - wk1r * x0i;
-    a[j2 + 3] = wk1i * x0i + wk1r * x0r;
-    x0r = x1r - x3i;
-    x0i = x1i - x3r;
-    a[j3 + 2] = wk3i * x0r + wk3r * x0i;
-    a[j3 + 3] = wk3i * x0i - wk3r * x0r;
-}
-
-
-#ifdef USE_CDFT_THREADS
-struct cdft_arg_st
-{
-    int n0;
-    int n;
-    double *a;
-    int nw;
-    double *w;
-};
-typedef struct cdft_arg_st cdft_arg_t;
-
-
-void cftrec4_th(int n, double *a, int nw, double *w)
-{
-    void *cftrec1_th(void *p);
-    void *cftrec2_th(void *p);
-    int i, idiv4, m, nthread;
-    cdft_thread_t th[4];
-    cdft_arg_t ag[4];
-
-    nthread = 2;
-    idiv4 = 0;
-    m = n >> 1;
-    if (n > CDFT_4THREADS_BEGIN_N)
-    {
-        nthread = 4;
-        idiv4 = 1;
-        m >>= 1;
-    }
-    for (i = 0; i < nthread; i++)
-    {
-        ag[i].n0 = n;
-        ag[i].n = m;
-        ag[i].a = &a[i * m];
-        ag[i].nw = nw;
-        ag[i].w = w;
-        if (i != idiv4)
-        {
-            cdft_thread_create(&th[i], cftrec1_th, &ag[i]);
-        }
-        else
-        {
-            cdft_thread_create(&th[i], cftrec2_th, &ag[i]);
-        }
-    }
-    for (i = 0; i < nthread; i++)
-    {
-        cdft_thread_wait(th[i]);
-    }
-}
-
-
-void *cftrec1_th(void *p)
-{
-    int cfttree(int n, int j, int k, double *a, int nw, double *w);
-    void cftleaf(int n, int isplt, double *a, int nw, double *w);
-    void cftmdl1(int n, double *a, double *w);
-    int isplt, j, k, m, n, n0, nw;
-    double *a, *w;
-
-    n0 = ((cdft_arg_t *) p)->n0;
-    n = ((cdft_arg_t *) p)->n;
-    a = ((cdft_arg_t *) p)->a;
-    nw = ((cdft_arg_t *) p)->nw;
-    w = ((cdft_arg_t *) p)->w;
-    m = n0;
-    while (m > 512)
-    {
-        m >>= 2;
-        cftmdl1(m, &a[n - m], &w[nw - (m >> 1)]);
-    }
-    cftleaf(m, 1, &a[n - m], nw, w);
-    k = 0;
-    for (j = n - m; j > 0; j -= m)
-    {
-        k++;
-        isplt = cfttree(m, j, k, a, nw, w);
-        cftleaf(m, isplt, &a[j - m], nw, w);
-    }
-    return (void *) 0;
-}
-
-
-void *cftrec2_th(void *p)
-{
-    int cfttree(int n, int j, int k, double *a, int nw, double *w);
-    void cftleaf(int n, int isplt, double *a, int nw, double *w);
-    void cftmdl2(int n, double *a, double *w);
-    int isplt, j, k, m, n, n0, nw;
-    double *a, *w;
-
-    n0 = ((cdft_arg_t *) p)->n0;
-    n = ((cdft_arg_t *) p)->n;
-    a = ((cdft_arg_t *) p)->a;
-    nw = ((cdft_arg_t *) p)->nw;
-    w = ((cdft_arg_t *) p)->w;
-    k = 1;
-    m = n0;
-    while (m > 512)
-    {
-        m >>= 2;
-        k <<= 2;
-        cftmdl2(m, &a[n - m], &w[nw - m]);
-    }
-    cftleaf(m, 0, &a[n - m], nw, w);
-    k >>= 1;
-    for (j = n - m; j > 0; j -= m)
-    {
-        k++;
-        isplt = cfttree(m, j, k, a, nw, w);
-        cftleaf(m, isplt, &a[j - m], nw, w);
-    }
-    return (void *) 0;
-}
-#endif /* USE_CDFT_THREADS */
-
-
-void cftrec4(int n, double *a, int nw, double *w)
-{
-    int cfttree(int n, int j, int k, double *a, int nw, double *w);
-    void cftleaf(int n, int isplt, double *a, int nw, double *w);
-    void cftmdl1(int n, double *a, double *w);
-    int isplt, j, k, m;
-
-    m = n;
-    while (m > 512)
-    {
-        m >>= 2;
-        cftmdl1(m, &a[n - m], &w[nw - (m >> 1)]);
-    }
-    cftleaf(m, 1, &a[n - m], nw, w);
-    k = 0;
-    for (j = n - m; j > 0; j -= m)
-    {
-        k++;
-        isplt = cfttree(m, j, k, a, nw, w);
-        cftleaf(m, isplt, &a[j - m], nw, w);
-    }
-}
-
-
-int cfttree(int n, int j, int k, double *a, int nw, double *w)
-{
-    void cftmdl1(int n, double *a, double *w);
-    void cftmdl2(int n, double *a, double *w);
-    int i, isplt, m;
-
-    if ((k & 3) != 0)
-    {
-        isplt = k & 1;
-        if (isplt != 0)
-        {
-            cftmdl1(n, &a[j - n], &w[nw - (n >> 1)]);
-        }
-        else
-        {
-            cftmdl2(n, &a[j - n], &w[nw - n]);
-        }
-    }
-    else
-    {
-        m = n;
-        for (i = k; (i & 3) == 0; i >>= 2)
-        {
-            m <<= 2;
-        }
-        isplt = i & 1;
-        if (isplt != 0)
-        {
-            while (m > 128)
-            {
-                cftmdl1(m, &a[j - m], &w[nw - (m >> 1)]);
-                m >>= 2;
-            }
-        }
-        else
-        {
-            while (m > 128)
-            {
-                cftmdl2(m, &a[j - m], &w[nw - m]);
-                m >>= 2;
-            }
-        }
-    }
-    return isplt;
-}
-
-
-void cftleaf(int n, int isplt, double *a, int nw, double *w)
-{
-    void cftmdl1(int n, double *a, double *w);
-    void cftmdl2(int n, double *a, double *w);
-    void cftf161(double *a, double *w);
-    void cftf162(double *a, double *w);
-    void cftf081(double *a, double *w);
-    void cftf082(double *a, double *w);
-
-    if (n == 512)
-    {
-        cftmdl1(128, a, &w[nw - 64]);
-        cftf161(a, &w[nw - 8]);
-        cftf162(&a[32], &w[nw - 32]);
-        cftf161(&a[64], &w[nw - 8]);
-        cftf161(&a[96], &w[nw - 8]);
-        cftmdl2(128, &a[128], &w[nw - 128]);
-        cftf161(&a[128], &w[nw - 8]);
-        cftf162(&a[160], &w[nw - 32]);
-        cftf161(&a[192], &w[nw - 8]);
-        cftf162(&a[224], &w[nw - 32]);
-        cftmdl1(128, &a[256], &w[nw - 64]);
-        cftf161(&a[256], &w[nw - 8]);
-        cftf162(&a[288], &w[nw - 32]);
-        cftf161(&a[320], &w[nw - 8]);
-        cftf161(&a[352], &w[nw - 8]);
-        if (isplt != 0)
-        {
-            cftmdl1(128, &a[384], &w[nw - 64]);
-            cftf161(&a[480], &w[nw - 8]);
-        }
-        else
-        {
-            cftmdl2(128, &a[384], &w[nw - 128]);
-            cftf162(&a[480], &w[nw - 32]);
-        }
-        cftf161(&a[384], &w[nw - 8]);
-        cftf162(&a[416], &w[nw - 32]);
-        cftf161(&a[448], &w[nw - 8]);
-    }
-    else
-    {
-        cftmdl1(64, a, &w[nw - 32]);
-        cftf081(a, &w[nw - 8]);
-        cftf082(&a[16], &w[nw - 8]);
-        cftf081(&a[32], &w[nw - 8]);
-        cftf081(&a[48], &w[nw - 8]);
-        cftmdl2(64, &a[64], &w[nw - 64]);
-        cftf081(&a[64], &w[nw - 8]);
-        cftf082(&a[80], &w[nw - 8]);
-        cftf081(&a[96], &w[nw - 8]);
-        cftf082(&a[112], &w[nw - 8]);
-        cftmdl1(64, &a[128], &w[nw - 32]);
-        cftf081(&a[128], &w[nw - 8]);
-        cftf082(&a[144], &w[nw - 8]);
-        cftf081(&a[160], &w[nw - 8]);
-        cftf081(&a[176], &w[nw - 8]);
-        if (isplt != 0)
-        {
-            cftmdl1(64, &a[192], &w[nw - 32]);
-            cftf081(&a[240], &w[nw - 8]);
-        }
-        else
-        {
-            cftmdl2(64, &a[192], &w[nw - 64]);
-            cftf082(&a[240], &w[nw - 8]);
-        }
-        cftf081(&a[192], &w[nw - 8]);
-        cftf082(&a[208], &w[nw - 8]);
-        cftf081(&a[224], &w[nw - 8]);
-    }
-}
-
-
-void cftmdl1(int n, double *a, double *w)
-{
-    int j, j0, j1, j2, j3, k, m, mh;
-    double wn4r, wk1r, wk1i, wk3r, wk3i;
-    double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
-    mh = n >> 3;
-    m = 2 * mh;
-    j1 = m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[0] + a[j2];
-    x0i = a[1] + a[j2 + 1];
-    x1r = a[0] - a[j2];
-    x1i = a[1] - a[j2 + 1];
-    x2r = a[j1] + a[j3];
-    x2i = a[j1 + 1] + a[j3 + 1];
-    x3r = a[j1] - a[j3];
-    x3i = a[j1 + 1] - a[j3 + 1];
-    a[0] = x0r + x2r;
-    a[1] = x0i + x2i;
-    a[j1] = x0r - x2r;
-    a[j1 + 1] = x0i - x2i;
-    a[j2] = x1r - x3i;
-    a[j2 + 1] = x1i + x3r;
-    a[j3] = x1r + x3i;
-    a[j3 + 1] = x1i - x3r;
-    wn4r = w[1];
-    k = 0;
-    for (j = 2; j < mh; j += 2)
-    {
-        k += 4;
-        wk1r = w[k];
-        wk1i = w[k + 1];
-        wk3r = w[k + 2];
-        wk3i = w[k + 3];
-        j1 = j + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j] + a[j2];
-        x0i = a[j + 1] + a[j2 + 1];
-        x1r = a[j] - a[j2];
-        x1i = a[j + 1] - a[j2 + 1];
-        x2r = a[j1] + a[j3];
-        x2i = a[j1 + 1] + a[j3 + 1];
-        x3r = a[j1] - a[j3];
-        x3i = a[j1 + 1] - a[j3 + 1];
-        a[j] = x0r + x2r;
-        a[j + 1] = x0i + x2i;
-        a[j1] = x0r - x2r;
-        a[j1 + 1] = x0i - x2i;
-        x0r = x1r - x3i;
-        x0i = x1i + x3r;
-        a[j2] = wk1r * x0r - wk1i * x0i;
-        a[j2 + 1] = wk1r * x0i + wk1i * x0r;
-        x0r = x1r + x3i;
-        x0i = x1i - x3r;
-        a[j3] = wk3r * x0r + wk3i * x0i;
-        a[j3 + 1] = wk3r * x0i - wk3i * x0r;
-        j0 = m - j;
-        j1 = j0 + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j0] + a[j2];
-        x0i = a[j0 + 1] + a[j2 + 1];
-        x1r = a[j0] - a[j2];
-        x1i = a[j0 + 1] - a[j2 + 1];
-        x2r = a[j1] + a[j3];
-        x2i = a[j1 + 1] + a[j3 + 1];
-        x3r = a[j1] - a[j3];
-        x3i = a[j1 + 1] - a[j3 + 1];
-        a[j0] = x0r + x2r;
-        a[j0 + 1] = x0i + x2i;
-        a[j1] = x0r - x2r;
-        a[j1 + 1] = x0i - x2i;
-        x0r = x1r - x3i;
-        x0i = x1i + x3r;
-        a[j2] = wk1i * x0r - wk1r * x0i;
-        a[j2 + 1] = wk1i * x0i + wk1r * x0r;
-        x0r = x1r + x3i;
-        x0i = x1i - x3r;
-        a[j3] = wk3i * x0r + wk3r * x0i;
-        a[j3 + 1] = wk3i * x0i - wk3r * x0r;
-    }
-    j0 = mh;
-    j1 = j0 + m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[j0] + a[j2];
-    x0i = a[j0 + 1] + a[j2 + 1];
-    x1r = a[j0] - a[j2];
-    x1i = a[j0 + 1] - a[j2 + 1];
-    x2r = a[j1] + a[j3];
-    x2i = a[j1 + 1] + a[j3 + 1];
-    x3r = a[j1] - a[j3];
-    x3i = a[j1 + 1] - a[j3 + 1];
-    a[j0] = x0r + x2r;
-    a[j0 + 1] = x0i + x2i;
-    a[j1] = x0r - x2r;
-    a[j1 + 1] = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    a[j2] = wn4r * (x0r - x0i);
-    a[j2 + 1] = wn4r * (x0i + x0r);
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    a[j3] = -wn4r * (x0r + x0i);
-    a[j3 + 1] = -wn4r * (x0i - x0r);
-}
-
-
-void cftmdl2(int n, double *a, double *w)
-{
-    int j, j0, j1, j2, j3, k, kr, m, mh;
-    double wn4r, wk1r, wk1i, wk3r, wk3i, wd1r, wd1i, wd3r, wd3i;
-    double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i, y0r, y0i, y2r, y2i;
-
-    mh = n >> 3;
-    m = 2 * mh;
-    wn4r = w[1];
-    j1 = m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[0] - a[j2 + 1];
-    x0i = a[1] + a[j2];
-    x1r = a[0] + a[j2 + 1];
-    x1i = a[1] - a[j2];
-    x2r = a[j1] - a[j3 + 1];
-    x2i = a[j1 + 1] + a[j3];
-    x3r = a[j1] + a[j3 + 1];
-    x3i = a[j1 + 1] - a[j3];
-    y0r = wn4r * (x2r - x2i);
-    y0i = wn4r * (x2i + x2r);
-    a[0] = x0r + y0r;
-    a[1] = x0i + y0i;
-    a[j1] = x0r - y0r;
-    a[j1 + 1] = x0i - y0i;
-    y0r = wn4r * (x3r - x3i);
-    y0i = wn4r * (x3i + x3r);
-    a[j2] = x1r - y0i;
-    a[j2 + 1] = x1i + y0r;
-    a[j3] = x1r + y0i;
-    a[j3 + 1] = x1i - y0r;
-    k = 0;
-    kr = 2 * m;
-    for (j = 2; j < mh; j += 2)
-    {
-        k += 4;
-        wk1r = w[k];
-        wk1i = w[k + 1];
-        wk3r = w[k + 2];
-        wk3i = w[k + 3];
-        kr -= 4;
-        wd1i = w[kr];
-        wd1r = w[kr + 1];
-        wd3i = w[kr + 2];
-        wd3r = w[kr + 3];
-        j1 = j + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j] - a[j2 + 1];
-        x0i = a[j + 1] + a[j2];
-        x1r = a[j] + a[j2 + 1];
-        x1i = a[j + 1] - a[j2];
-        x2r = a[j1] - a[j3 + 1];
-        x2i = a[j1 + 1] + a[j3];
-        x3r = a[j1] + a[j3 + 1];
-        x3i = a[j1 + 1] - a[j3];
-        y0r = wk1r * x0r - wk1i * x0i;
-        y0i = wk1r * x0i + wk1i * x0r;
-        y2r = wd1r * x2r - wd1i * x2i;
-        y2i = wd1r * x2i + wd1i * x2r;
-        a[j] = y0r + y2r;
-        a[j + 1] = y0i + y2i;
-        a[j1] = y0r - y2r;
-        a[j1 + 1] = y0i - y2i;
-        y0r = wk3r * x1r + wk3i * x1i;
-        y0i = wk3r * x1i - wk3i * x1r;
-        y2r = wd3r * x3r + wd3i * x3i;
-        y2i = wd3r * x3i - wd3i * x3r;
-        a[j2] = y0r + y2r;
-        a[j2 + 1] = y0i + y2i;
-        a[j3] = y0r - y2r;
-        a[j3 + 1] = y0i - y2i;
-        j0 = m - j;
-        j1 = j0 + m;
-        j2 = j1 + m;
-        j3 = j2 + m;
-        x0r = a[j0] - a[j2 + 1];
-        x0i = a[j0 + 1] + a[j2];
-        x1r = a[j0] + a[j2 + 1];
-        x1i = a[j0 + 1] - a[j2];
-        x2r = a[j1] - a[j3 + 1];
-        x2i = a[j1 + 1] + a[j3];
-        x3r = a[j1] + a[j3 + 1];
-        x3i = a[j1 + 1] - a[j3];
-        y0r = wd1i * x0r - wd1r * x0i;
-        y0i = wd1i * x0i + wd1r * x0r;
-        y2r = wk1i * x2r - wk1r * x2i;
-        y2i = wk1i * x2i + wk1r * x2r;
-        a[j0] = y0r + y2r;
-        a[j0 + 1] = y0i + y2i;
-        a[j1] = y0r - y2r;
-        a[j1 + 1] = y0i - y2i;
-        y0r = wd3i * x1r + wd3r * x1i;
-        y0i = wd3i * x1i - wd3r * x1r;
-        y2r = wk3i * x3r + wk3r * x3i;
-        y2i = wk3i * x3i - wk3r * x3r;
-        a[j2] = y0r + y2r;
-        a[j2 + 1] = y0i + y2i;
-        a[j3] = y0r - y2r;
-        a[j3 + 1] = y0i - y2i;
-    }
-    wk1r = w[m];
-    wk1i = w[m + 1];
-    j0 = mh;
-    j1 = j0 + m;
-    j2 = j1 + m;
-    j3 = j2 + m;
-    x0r = a[j0] - a[j2 + 1];
-    x0i = a[j0 + 1] + a[j2];
-    x1r = a[j0] + a[j2 + 1];
-    x1i = a[j0 + 1] - a[j2];
-    x2r = a[j1] - a[j3 + 1];
-    x2i = a[j1 + 1] + a[j3];
-    x3r = a[j1] + a[j3 + 1];
-    x3i = a[j1 + 1] - a[j3];
-    y0r = wk1r * x0r - wk1i * x0i;
-    y0i = wk1r * x0i + wk1i * x0r;
-    y2r = wk1i * x2r - wk1r * x2i;
-    y2i = wk1i * x2i + wk1r * x2r;
-    a[j0] = y0r + y2r;
-    a[j0 + 1] = y0i + y2i;
-    a[j1] = y0r - y2r;
-    a[j1 + 1] = y0i - y2i;
-    y0r = wk1i * x1r - wk1r * x1i;
-    y0i = wk1i * x1i + wk1r * x1r;
-    y2r = wk1r * x3r - wk1i * x3i;
-    y2i = wk1r * x3i + wk1i * x3r;
-    a[j2] = y0r - y2r;
-    a[j2 + 1] = y0i - y2i;
-    a[j3] = y0r + y2r;
-    a[j3 + 1] = y0i + y2i;
-}
-
-
-void cftfx41(int n, double *a, int nw, double *w)
-{
-    void cftf161(double *a, double *w);
-    void cftf162(double *a, double *w);
-    void cftf081(double *a, double *w);
-    void cftf082(double *a, double *w);
-
-    if (n == 128)
-    {
-        cftf161(a, &w[nw - 8]);
-        cftf162(&a[32], &w[nw - 32]);
-        cftf161(&a[64], &w[nw - 8]);
-        cftf161(&a[96], &w[nw - 8]);
-    }
-    else
-    {
-        cftf081(a, &w[nw - 8]);
-        cftf082(&a[16], &w[nw - 8]);
-        cftf081(&a[32], &w[nw - 8]);
-        cftf081(&a[48], &w[nw - 8]);
-    }
-}
-
-
-void cftf161(double *a, double *w)
-{
-    double wn4r, wk1r, wk1i,
-           x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i,
-           y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i,
-           y4r, y4i, y5r, y5i, y6r, y6i, y7r, y7i,
-           y8r, y8i, y9r, y9i, y10r, y10i, y11r, y11i,
-           y12r, y12i, y13r, y13i, y14r, y14i, y15r, y15i;
-
-    wn4r = w[1];
-    wk1r = w[2];
-    wk1i = w[3];
-    x0r = a[0] + a[16];
-    x0i = a[1] + a[17];
-    x1r = a[0] - a[16];
-    x1i = a[1] - a[17];
-    x2r = a[8] + a[24];
-    x2i = a[9] + a[25];
-    x3r = a[8] - a[24];
-    x3i = a[9] - a[25];
-    y0r = x0r + x2r;
-    y0i = x0i + x2i;
-    y4r = x0r - x2r;
-    y4i = x0i - x2i;
-    y8r = x1r - x3i;
-    y8i = x1i + x3r;
-    y12r = x1r + x3i;
-    y12i = x1i - x3r;
-    x0r = a[2] + a[18];
-    x0i = a[3] + a[19];
-    x1r = a[2] - a[18];
-    x1i = a[3] - a[19];
-    x2r = a[10] + a[26];
-    x2i = a[11] + a[27];
-    x3r = a[10] - a[26];
-    x3i = a[11] - a[27];
-    y1r = x0r + x2r;
-    y1i = x0i + x2i;
-    y5r = x0r - x2r;
-    y5i = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    y9r = wk1r * x0r - wk1i * x0i;
-    y9i = wk1r * x0i + wk1i * x0r;
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    y13r = wk1i * x0r - wk1r * x0i;
-    y13i = wk1i * x0i + wk1r * x0r;
-    x0r = a[4] + a[20];
-    x0i = a[5] + a[21];
-    x1r = a[4] - a[20];
-    x1i = a[5] - a[21];
-    x2r = a[12] + a[28];
-    x2i = a[13] + a[29];
-    x3r = a[12] - a[28];
-    x3i = a[13] - a[29];
-    y2r = x0r + x2r;
-    y2i = x0i + x2i;
-    y6r = x0r - x2r;
-    y6i = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    y10r = wn4r * (x0r - x0i);
-    y10i = wn4r * (x0i + x0r);
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    y14r = wn4r * (x0r + x0i);
-    y14i = wn4r * (x0i - x0r);
-    x0r = a[6] + a[22];
-    x0i = a[7] + a[23];
-    x1r = a[6] - a[22];
-    x1i = a[7] - a[23];
-    x2r = a[14] + a[30];
-    x2i = a[15] + a[31];
-    x3r = a[14] - a[30];
-    x3i = a[15] - a[31];
-    y3r = x0r + x2r;
-    y3i = x0i + x2i;
-    y7r = x0r - x2r;
-    y7i = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    y11r = wk1i * x0r - wk1r * x0i;
-    y11i = wk1i * x0i + wk1r * x0r;
-    x0r = x1r + x3i;
-    x0i = x1i - x3r;
-    y15r = wk1r * x0r - wk1i * x0i;
-    y15i = wk1r * x0i + wk1i * x0r;
-    x0r = y12r - y14r;
-    x0i = y12i - y14i;
-    x1r = y12r + y14r;
-    x1i = y12i + y14i;
-    x2r = y13r - y15r;
-    x2i = y13i - y15i;
-    x3r = y13r + y15r;
-    x3i = y13i + y15i;
-    a[24] = x0r + x2r;
-    a[25] = x0i + x2i;
-    a[26] = x0r - x2r;
-    a[27] = x0i - x2i;
-    a[28] = x1r - x3i;
-    a[29] = x1i + x3r;
-    a[30] = x1r + x3i;
-    a[31] = x1i - x3r;
-    x0r = y8r + y10r;
-    x0i = y8i + y10i;
-    x1r = y8r - y10r;
-    x1i = y8i - y10i;
-    x2r = y9r + y11r;
-    x2i = y9i + y11i;
-    x3r = y9r - y11r;
-    x3i = y9i - y11i;
-    a[16] = x0r + x2r;
-    a[17] = x0i + x2i;
-    a[18] = x0r - x2r;
-    a[19] = x0i - x2i;
-    a[20] = x1r - x3i;
-    a[21] = x1i + x3r;
-    a[22] = x1r + x3i;
-    a[23] = x1i - x3r;
-    x0r = y5r - y7i;
-    x0i = y5i + y7r;
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    x0r = y5r + y7i;
-    x0i = y5i - y7r;
-    x3r = wn4r * (x0r - x0i);
-    x3i = wn4r * (x0i + x0r);
-    x0r = y4r - y6i;
-    x0i = y4i + y6r;
-    x1r = y4r + y6i;
-    x1i = y4i - y6r;
-    a[8] = x0r + x2r;
-    a[9] = x0i + x2i;
-    a[10] = x0r - x2r;
-    a[11] = x0i - x2i;
-    a[12] = x1r - x3i;
-    a[13] = x1i + x3r;
-    a[14] = x1r + x3i;
-    a[15] = x1i - x3r;
-    x0r = y0r + y2r;
-    x0i = y0i + y2i;
-    x1r = y0r - y2r;
-    x1i = y0i - y2i;
-    x2r = y1r + y3r;
-    x2i = y1i + y3i;
-    x3r = y1r - y3r;
-    x3i = y1i - y3i;
-    a[0] = x0r + x2r;
-    a[1] = x0i + x2i;
-    a[2] = x0r - x2r;
-    a[3] = x0i - x2i;
-    a[4] = x1r - x3i;
-    a[5] = x1i + x3r;
-    a[6] = x1r + x3i;
-    a[7] = x1i - x3r;
-}
-
-
-void cftf162(double *a, double *w)
-{
-    double wn4r, wk1r, wk1i, wk2r, wk2i, wk3r, wk3i,
-           x0r, x0i, x1r, x1i, x2r, x2i,
-           y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i,
-           y4r, y4i, y5r, y5i, y6r, y6i, y7r, y7i,
-           y8r, y8i, y9r, y9i, y10r, y10i, y11r, y11i,
-           y12r, y12i, y13r, y13i, y14r, y14i, y15r, y15i;
-
-    wn4r = w[1];
-    wk1r = w[4];
-    wk1i = w[5];
-    wk3r = w[6];
-    wk3i = -w[7];
-    wk2r = w[8];
-    wk2i = w[9];
-    x1r = a[0] - a[17];
-    x1i = a[1] + a[16];
-    x0r = a[8] - a[25];
-    x0i = a[9] + a[24];
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    y0r = x1r + x2r;
-    y0i = x1i + x2i;
-    y4r = x1r - x2r;
-    y4i = x1i - x2i;
-    x1r = a[0] + a[17];
-    x1i = a[1] - a[16];
-    x0r = a[8] + a[25];
-    x0i = a[9] - a[24];
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    y8r = x1r - x2i;
-    y8i = x1i + x2r;
-    y12r = x1r + x2i;
-    y12i = x1i - x2r;
-    x0r = a[2] - a[19];
-    x0i = a[3] + a[18];
-    x1r = wk1r * x0r - wk1i * x0i;
-    x1i = wk1r * x0i + wk1i * x0r;
-    x0r = a[10] - a[27];
-    x0i = a[11] + a[26];
-    x2r = wk3i * x0r - wk3r * x0i;
-    x2i = wk3i * x0i + wk3r * x0r;
-    y1r = x1r + x2r;
-    y1i = x1i + x2i;
-    y5r = x1r - x2r;
-    y5i = x1i - x2i;
-    x0r = a[2] + a[19];
-    x0i = a[3] - a[18];
-    x1r = wk3r * x0r - wk3i * x0i;
-    x1i = wk3r * x0i + wk3i * x0r;
-    x0r = a[10] + a[27];
-    x0i = a[11] - a[26];
-    x2r = wk1r * x0r + wk1i * x0i;
-    x2i = wk1r * x0i - wk1i * x0r;
-    y9r = x1r - x2r;
-    y9i = x1i - x2i;
-    y13r = x1r + x2r;
-    y13i = x1i + x2i;
-    x0r = a[4] - a[21];
-    x0i = a[5] + a[20];
-    x1r = wk2r * x0r - wk2i * x0i;
-    x1i = wk2r * x0i + wk2i * x0r;
-    x0r = a[12] - a[29];
-    x0i = a[13] + a[28];
-    x2r = wk2i * x0r - wk2r * x0i;
-    x2i = wk2i * x0i + wk2r * x0r;
-    y2r = x1r + x2r;
-    y2i = x1i + x2i;
-    y6r = x1r - x2r;
-    y6i = x1i - x2i;
-    x0r = a[4] + a[21];
-    x0i = a[5] - a[20];
-    x1r = wk2i * x0r - wk2r * x0i;
-    x1i = wk2i * x0i + wk2r * x0r;
-    x0r = a[12] + a[29];
-    x0i = a[13] - a[28];
-    x2r = wk2r * x0r - wk2i * x0i;
-    x2i = wk2r * x0i + wk2i * x0r;
-    y10r = x1r - x2r;
-    y10i = x1i - x2i;
-    y14r = x1r + x2r;
-    y14i = x1i + x2i;
-    x0r = a[6] - a[23];
-    x0i = a[7] + a[22];
-    x1r = wk3r * x0r - wk3i * x0i;
-    x1i = wk3r * x0i + wk3i * x0r;
-    x0r = a[14] - a[31];
-    x0i = a[15] + a[30];
-    x2r = wk1i * x0r - wk1r * x0i;
-    x2i = wk1i * x0i + wk1r * x0r;
-    y3r = x1r + x2r;
-    y3i = x1i + x2i;
-    y7r = x1r - x2r;
-    y7i = x1i - x2i;
-    x0r = a[6] + a[23];
-    x0i = a[7] - a[22];
-    x1r = wk1i * x0r + wk1r * x0i;
-    x1i = wk1i * x0i - wk1r * x0r;
-    x0r = a[14] + a[31];
-    x0i = a[15] - a[30];
-    x2r = wk3i * x0r - wk3r * x0i;
-    x2i = wk3i * x0i + wk3r * x0r;
-    y11r = x1r + x2r;
-    y11i = x1i + x2i;
-    y15r = x1r - x2r;
-    y15i = x1i - x2i;
-    x1r = y0r + y2r;
-    x1i = y0i + y2i;
-    x2r = y1r + y3r;
-    x2i = y1i + y3i;
-    a[0] = x1r + x2r;
-    a[1] = x1i + x2i;
-    a[2] = x1r - x2r;
-    a[3] = x1i - x2i;
-    x1r = y0r - y2r;
-    x1i = y0i - y2i;
-    x2r = y1r - y3r;
-    x2i = y1i - y3i;
-    a[4] = x1r - x2i;
-    a[5] = x1i + x2r;
-    a[6] = x1r + x2i;
-    a[7] = x1i - x2r;
-    x1r = y4r - y6i;
-    x1i = y4i + y6r;
-    x0r = y5r - y7i;
-    x0i = y5i + y7r;
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    a[8] = x1r + x2r;
-    a[9] = x1i + x2i;
-    a[10] = x1r - x2r;
-    a[11] = x1i - x2i;
-    x1r = y4r + y6i;
-    x1i = y4i - y6r;
-    x0r = y5r + y7i;
-    x0i = y5i - y7r;
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    a[12] = x1r - x2i;
-    a[13] = x1i + x2r;
-    a[14] = x1r + x2i;
-    a[15] = x1i - x2r;
-    x1r = y8r + y10r;
-    x1i = y8i + y10i;
-    x2r = y9r - y11r;
-    x2i = y9i - y11i;
-    a[16] = x1r + x2r;
-    a[17] = x1i + x2i;
-    a[18] = x1r - x2r;
-    a[19] = x1i - x2i;
-    x1r = y8r - y10r;
-    x1i = y8i - y10i;
-    x2r = y9r + y11r;
-    x2i = y9i + y11i;
-    a[20] = x1r - x2i;
-    a[21] = x1i + x2r;
-    a[22] = x1r + x2i;
-    a[23] = x1i - x2r;
-    x1r = y12r - y14i;
-    x1i = y12i + y14r;
-    x0r = y13r + y15i;
-    x0i = y13i - y15r;
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    a[24] = x1r + x2r;
-    a[25] = x1i + x2i;
-    a[26] = x1r - x2r;
-    a[27] = x1i - x2i;
-    x1r = y12r + y14i;
-    x1i = y12i - y14r;
-    x0r = y13r - y15i;
-    x0i = y13i + y15r;
-    x2r = wn4r * (x0r - x0i);
-    x2i = wn4r * (x0i + x0r);
-    a[28] = x1r - x2i;
-    a[29] = x1i + x2r;
-    a[30] = x1r + x2i;
-    a[31] = x1i - x2r;
-}
-
-
-void cftf081(double *a, double *w)
-{
-    double wn4r, x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i,
-           y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i,
-           y4r, y4i, y5r, y5i, y6r, y6i, y7r, y7i;
-
-    wn4r = w[1];
-    x0r = a[0] + a[8];
-    x0i = a[1] + a[9];
-    x1r = a[0] - a[8];
-    x1i = a[1] - a[9];
-    x2r = a[4] + a[12];
-    x2i = a[5] + a[13];
-    x3r = a[4] - a[12];
-    x3i = a[5] - a[13];
-    y0r = x0r + x2r;
-    y0i = x0i + x2i;
-    y2r = x0r - x2r;
-    y2i = x0i - x2i;
-    y1r = x1r - x3i;
-    y1i = x1i + x3r;
-    y3r = x1r + x3i;
-    y3i = x1i - x3r;
-    x0r = a[2] + a[10];
-    x0i = a[3] + a[11];
-    x1r = a[2] - a[10];
-    x1i = a[3] - a[11];
-    x2r = a[6] + a[14];
-    x2i = a[7] + a[15];
-    x3r = a[6] - a[14];
-    x3i = a[7] - a[15];
-    y4r = x0r + x2r;
-    y4i = x0i + x2i;
-    y6r = x0r - x2r;
-    y6i = x0i - x2i;
-    x0r = x1r - x3i;
-    x0i = x1i + x3r;
-    x2r = x1r + x3i;
-    x2i = x1i - x3r;
-    y5r = wn4r * (x0r - x0i);
-    y5i = wn4r * (x0r + x0i);
-    y7r = wn4r * (x2r - x2i);
-    y7i = wn4r * (x2r + x2i);
-    a[8] = y1r + y5r;
-    a[9] = y1i + y5i;
-    a[10] = y1r - y5r;
-    a[11] = y1i - y5i;
-    a[12] = y3r - y7i;
-    a[13] = y3i + y7r;
-    a[14] = y3r + y7i;
-    a[15] = y3i - y7r;
-    a[0] = y0r + y4r;
-    a[1] = y0i + y4i;
-    a[2] = y0r - y4r;
-    a[3] = y0i - y4i;
-    a[4] = y2r - y6i;
-    a[5] = y2i + y6r;
-    a[6] = y2r + y6i;
-    a[7] = y2i - y6r;
-}
-
-
-void cftf082(double *a, double *w)
-{
-    double wn4r, wk1r, wk1i, x0r, x0i, x1r, x1i,
-           y0r, y0i, y1r, y1i, y2r, y2i, y3r, y3i,
-           y4r, y4i, y5r, y5i, y6r, y6i, y7r, y7i;
-
-    wn4r = w[1];
-    wk1r = w[2];
-    wk1i = w[3];
-    y0r = a[0] - a[9];
-    y0i = a[1] + a[8];
-    y1r = a[0] + a[9];
-    y1i = a[1] - a[8];
-    x0r = a[4] - a[13];
-    x0i = a[5] + a[12];
-    y2r = wn4r * (x0r - x0i);
-    y2i = wn4r * (x0i + x0r);
-    x0r = a[4] + a[13];
-    x0i = a[5] - a[12];
-    y3r = wn4r * (x0r - x0i);
-    y3i = wn4r * (x0i + x0r);
-    x0r = a[2] - a[11];
-    x0i = a[3] + a[10];
-    y4r = wk1r * x0r - wk1i * x0i;
-    y4i = wk1r * x0i + wk1i * x0r;
-    x0r = a[2] + a[11];
-    x0i = a[3] - a[10];
-    y5r = wk1i * x0r - wk1r * x0i;
-    y5i = wk1i * x0i + wk1r * x0r;
-    x0r = a[6] - a[15];
-    x0i = a[7] + a[14];
-    y6r = wk1i * x0r - wk1r * x0i;
-    y6i = wk1i * x0i + wk1r * x0r;
-    x0r = a[6] + a[15];
-    x0i = a[7] - a[14];
-    y7r = wk1r * x0r - wk1i * x0i;
-    y7i = wk1r * x0i + wk1i * x0r;
-    x0r = y0r + y2r;
-    x0i = y0i + y2i;
-    x1r = y4r + y6r;
-    x1i = y4i + y6i;
-    a[0] = x0r + x1r;
-    a[1] = x0i + x1i;
-    a[2] = x0r - x1r;
-    a[3] = x0i - x1i;
-    x0r = y0r - y2r;
-    x0i = y0i - y2i;
-    x1r = y4r - y6r;
-    x1i = y4i - y6i;
-    a[4] = x0r - x1i;
-    a[5] = x0i + x1r;
-    a[6] = x0r + x1i;
-    a[7] = x0i - x1r;
-    x0r = y1r - y3i;
-    x0i = y1i + y3r;
-    x1r = y5r - y7r;
-    x1i = y5i - y7i;
-    a[8] = x0r + x1r;
-    a[9] = x0i + x1i;
-    a[10] = x0r - x1r;
-    a[11] = x0i - x1i;
-    x0r = y1r + y3i;
-    x0i = y1i - y3r;
-    x1r = y5r + y7r;
-    x1i = y5i + y7i;
-    a[12] = x0r - x1i;
-    a[13] = x0i + x1r;
-    a[14] = x0r + x1i;
-    a[15] = x0i - x1r;
-}
-
-
-void cftf040(double *a)
-{
-    double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
-    x0r = a[0] + a[4];
-    x0i = a[1] + a[5];
-    x1r = a[0] - a[4];
-    x1i = a[1] - a[5];
-    x2r = a[2] + a[6];
-    x2i = a[3] + a[7];
-    x3r = a[2] - a[6];
-    x3i = a[3] - a[7];
-    a[0] = x0r + x2r;
-    a[1] = x0i + x2i;
-    a[2] = x1r - x3i;
-    a[3] = x1i + x3r;
-    a[4] = x0r - x2r;
-    a[5] = x0i - x2i;
-    a[6] = x1r + x3i;
-    a[7] = x1i - x3r;
-}
-
-
-void cftb040(double *a)
-{
-    double x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
-
-    x0r = a[0] + a[4];
-    x0i = a[1] + a[5];
-    x1r = a[0] - a[4];
-    x1i = a[1] - a[5];
-    x2r = a[2] + a[6];
-    x2i = a[3] + a[7];
-    x3r = a[2] - a[6];
-    x3i = a[3] - a[7];
-    a[0] = x0r + x2r;
-    a[1] = x0i + x2i;
-    a[2] = x1r + x3i;
-    a[3] = x1i - x3r;
-    a[4] = x0r - x2r;
-    a[5] = x0i - x2i;
-    a[6] = x1r - x3i;
-    a[7] = x1i + x3r;
-}
-
-
-void cftx020(double *a)
-{
-    double x0r, x0i;
-
-    x0r = a[0] - a[2];
-    x0i = a[1] - a[3];
-    a[0] += a[2];
-    a[1] += a[3];
-    a[2] = x0r;
-    a[3] = x0i;
-}
-
-
-void rftfsub(int n, double *a, int nc, double *c)
-{
-    int j, k, kk, ks, m;
-    double wkr, wki, xr, xi, yr, yi;
-
-    m = n >> 1;
-    ks = 2 * nc / m;
-    kk = 0;
-    for (j = 2; j < m; j += 2)
-    {
-        k = n - j;
-        kk += ks;
-        wkr = 0.5 - c[nc - kk];
-        wki = c[kk];
-        xr = a[j] - a[k];
-        xi = a[j + 1] + a[k + 1];
-        yr = wkr * xr - wki * xi;
-        yi = wkr * xi + wki * xr;
-        a[j] -= yr;
-        a[j + 1] -= yi;
-        a[k] += yr;
-        a[k + 1] -= yi;
-    }
-}
-
-
-void rftbsub(int n, double *a, int nc, double *c)
-{
-    int j, k, kk, ks, m;
-    double wkr, wki, xr, xi, yr, yi;
-
-    m = n >> 1;
-    ks = 2 * nc / m;
-    kk = 0;
-    for (j = 2; j < m; j += 2)
-    {
-        k = n - j;
-        kk += ks;
-        wkr = 0.5 - c[nc - kk];
-        wki = c[kk];
-        xr = a[j] - a[k];
-        xi = a[j + 1] + a[k + 1];
-        yr = wkr * xr + wki * xi;
-        yi = wkr * xi - wki * xr;
-        a[j] -= yr;
-        a[j + 1] -= yi;
-        a[k] += yr;
-        a[k + 1] -= yi;
-    }
-}
-
-
-void dctsub(int n, double *a, int nc, double *c)
-{
-    int j, k, kk, ks, m;
-    double wkr, wki, xr;
-
-    m = n >> 1;
-    ks = nc / n;
-    kk = 0;
-    for (j = 1; j < m; j++)
-    {
-        k = n - j;
-        kk += ks;
-        wkr = c[kk] - c[nc - kk];
-        wki = c[kk] + c[nc - kk];
-        xr = wki * a[j] - wkr * a[k];
-        a[j] = wkr * a[j] + wki * a[k];
-        a[k] = xr;
-    }
-    a[m] *= c[0];
-}
-
-
-void dstsub(int n, double *a, int nc, double *c)
-{
-    int j, k, kk, ks, m;
-    double wkr, wki, xr;
-
-    m = n >> 1;
-    ks = nc / n;
-    kk = 0;
-    for (j = 1; j < m; j++)
-    {
-        k = n - j;
-        kk += ks;
-        wkr = c[kk] - c[nc - kk];
-        wki = c[kk] + c[nc - kk];
-        xr = wki * a[k] - wkr * a[j];
-        a[k] = wkr * a[k] + wki * a[j];
-        a[j] = xr;
-    }
-    a[m] *= c[0];
-}
-
--- a/src/fftsg.h	Wed Jan 09 20:15:50 2013 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,21 +0,0 @@
-/* FFT functions */
-void cdft(int n, int isgn, double *a, int *ip, double *w);
-void rdft(int n, int isgn, double *a, int *ip, double *w);
-void ddct(int n, int isgn, double *a, int *ip, double *w);
-void ddst(int n, int isgn, double *a, int *ip, double *w);
-void dfct(int n, double *a, double *t, int *ip, double *w);
-void dfst(int n, double *a, double *t, int *ip, double *w);
-
-/* Auxiliary functions */
-void makewt(int nw, int *ip, double *w);
-void bitrv2(int n, int *ip, double *a);
-void bitrv2conj(int n, int *ip, double *a);
-void cftfsub(int n, double *a, double *w);
-void cftbsub(int n, double *a, double *w);
-void makect(int nc, int *ip, double *c);
-void rftfsub(int n, double *a, int nc, double *c);
-void rftbsub(int n, double *a, int nc, double *c);
-void dctsub(int n, double *a, int nc, double *c);
-void dstsub(int n, double *a, int nc, double *c);
-void cft1st(int n, double *a, double *w);
-void cftmdl(int n, int l, double *a, double *w);
--- a/src/helper.c	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/helper.c	Wed Jan 09 23:09:34 2013 +0000
@@ -23,8 +23,6 @@
 
 /* helper.c: helper functions. */
 
-#include <config.h>
-
 #include <stdio.h>
 
 #include "xtract/libxtract.h"
--- a/src/init.c	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/init.c	Wed Jan 09 23:09:34 2013 +0000
@@ -24,14 +24,14 @@
 /* init.c: defines initialisation and free functions. Also contains library constructor routine. */
 
 #ifdef HAVE_CONFIG_H
-#    include <config.h>
+#include <config.h>
 #endif
 
 #include <math.h>
 #include <stdlib.h>
 #include <stdio.h>
 
-#include "fftsg.h"
+#include "fft.h"
 
 #include "xtract/libxtract.h"
 #include "xtract_window_private.h"
@@ -39,6 +39,215 @@
 #include "xtract_globals_private.h"
 
 
+
+#ifdef USE_OOURA
+void xtract_init_ooura_data(xtract_ooura_data *ooura_data, unsigned int N)
+{
+    ooura_data->ooura_ip  = (int *)calloc((2 + sqrt(N)), sizeof(int));
+    ooura_data->ooura_w   = (double *)calloc((N - 1), sizeof(double));
+    ooura_data->initialised = true;
+}
+
+void xtract_free_ooura_data(xtract_ooura_data *ooura_data)
+{
+    free(ooura_data->ooura_ip);
+    free(ooura_data->ooura_w);
+    ooura_data->ooura_ip = NULL;
+    ooura_data->ooura_w = NULL;
+    ooura_data->initialised = false;
+}
+
+int xtract_init_ooura_(int N, int feature_name)
+{
+
+    int M = N >> 1;
+
+    if(feature_name == XTRACT_AUTOCORRELATION_FFT)
+    {
+        M = N; /* allow for zero padding */
+    }
+
+    switch(feature_name)
+    {
+    case XTRACT_SPECTRUM:
+        if(ooura_data_spectrum.initialised)
+        {
+            xtract_free_ooura_data(&ooura_data_spectrum);
+        }
+        xtract_init_ooura_data(&ooura_data_spectrum, M);
+        break;
+    case XTRACT_AUTOCORRELATION_FFT:
+        if(ooura_data_autocorrelation_fft.initialised)
+        {
+            xtract_free_ooura_data(&ooura_data_autocorrelation_fft);
+        }
+        xtract_init_ooura_data(&ooura_data_autocorrelation_fft, M);
+        break;
+    case XTRACT_DCT:
+        if(ooura_data_dct.initialised)
+        {
+            xtract_free_ooura_data(&ooura_data_dct);
+        }
+        xtract_init_ooura_data(&ooura_data_dct, M);
+    case XTRACT_MFCC:
+        if(ooura_data_mfcc.initialised)
+        {
+            xtract_free_ooura_data(&ooura_data_mfcc);
+        }
+        xtract_init_ooura_data(&ooura_data_mfcc, M);
+        break;
+    }
+
+    return XTRACT_SUCCESS;
+}
+
+void xtract_free_ooura_(void)
+{
+    if(ooura_data_spectrum.initialised)
+    {
+        xtract_free_ooura_data(&ooura_data_spectrum);
+    }
+    if(ooura_data_autocorrelation_fft.initialised)
+    {
+        xtract_free_ooura_data(&ooura_data_autocorrelation_fft);
+    }
+    if(ooura_data_dct.initialised)
+    {
+        xtract_free_ooura_data(&ooura_data_dct);
+    }
+    if(ooura_data_mfcc.initialised)
+    {
+        xtract_free_ooura_data(&ooura_data_mfcc);
+    }
+}
+
+#else
+
+void xtract_init_vdsp_data(xtract_vdsp_data *vdsp_data, unsigned int N)
+{
+    vdsp_data->setup = vDSP_create_fftsetupD(log2f(N), FFT_RADIX2);
+    vdsp_data->fft.realp = (double *) malloc((N >> 1) * sizeof(double));
+    vdsp_data->fft.imagp = (double *) malloc((N >> 1) * sizeof(double));
+    vdsp_data->log2N = log2f(N);
+    vdsp_data->initialised = true;
+}
+
+void xtract_free_vdsp_data(xtract_vdsp_data *vdsp_data)
+{
+    free(vdsp_data->fft.realp);
+    free(vdsp_data->fft.imagp);
+    vDSP_destroy_fftsetupD(vdsp_data->setup);
+    vdsp_data->fft.realp   = NULL;
+    vdsp_data->fft.imagp   = NULL;
+    vdsp_data->initialised = false;
+}
+
+int xtract_init_vdsp_(int N, int feature_name)
+{
+
+    int M = N >> 1;
+
+    if(feature_name == XTRACT_AUTOCORRELATION_FFT)
+    {
+        M = N; /* allow for zero padding */
+    }
+
+    switch(feature_name)
+    {
+    case XTRACT_SPECTRUM:
+        if(vdsp_data_spectrum.initialised)
+        {
+            xtract_free_vdsp_data(&vdsp_data_spectrum);
+        }
+        xtract_init_vdsp_data(&vdsp_data_spectrum, M);
+        break;
+    case XTRACT_AUTOCORRELATION_FFT:
+        if(vdsp_data_autocorrelation_fft.initialised)
+        {
+            xtract_free_vdsp_data(&vdsp_data_autocorrelation_fft);
+        }
+        xtract_init_vdsp_data(&vdsp_data_autocorrelation_fft, M);
+        break;
+    case XTRACT_DCT:
+        if(vdsp_data_dct.initialised)
+        {
+            xtract_free_vdsp_data(&vdsp_data_dct);
+        }
+        xtract_init_vdsp_data(&vdsp_data_dct, M);
+    case XTRACT_MFCC:
+        if(vdsp_data_mfcc.initialised)
+        {
+            xtract_free_vdsp_data(&vdsp_data_mfcc);
+        }
+        xtract_init_vdsp_data(&vdsp_data_mfcc, M);
+        break;
+    }
+
+    return XTRACT_SUCCESS;
+}
+
+void xtract_free_vdsp_(void)
+{
+    if(vdsp_data_spectrum.initialised)
+    {
+        xtract_free_vdsp_data(&vdsp_data_spectrum);
+    }
+    if(vdsp_data_autocorrelation_fft.initialised)
+    {
+        xtract_free_vdsp_data(&vdsp_data_autocorrelation_fft);
+    }
+    if(vdsp_data_dct.initialised)
+    {
+        xtract_free_vdsp_data(&vdsp_data_dct);
+    }
+    if(vdsp_data_mfcc.initialised)
+    {
+        xtract_free_vdsp_data(&vdsp_data_mfcc);
+    }
+}
+
+
+#endif
+
+int xtract_init_fft(int N, int feature_name)
+{
+    if(!xtract_is_poweroftwo(N))
+    {
+        fprintf(stderr,
+                "libxtract: error: only power-of-two FFT sizes are supported by Ooura FFT.\n");
+        exit(EXIT_FAILURE);
+    }
+#ifdef USE_OOURA
+    return xtract_init_ooura_(N, feature_name);
+#else
+    return xtract_init_vdsp_(N, feature_name);
+#endif
+}
+
+void xtract_free_fft(void)
+{
+#ifdef USE_OOURA
+    xtract_free_ooura_();
+#else
+    xtract_free_vdsp_();
+#endif
+}
+
+
+int xtract_init_bark(int N, double sr, int *band_limits)
+{
+
+    double  edges[] = {0, 100, 200, 300, 400, 510, 630, 770, 920, 1080, 1270, 1480, 1720, 2000, 2320, 2700, 3150, 3700, 4400, 5300, 6400, 7700, 9500, 12000, 15500, 20500, 27000}; /* Takes us up to sr = 54kHz (CCRMA: JOS)*/
+
+    int bands = XTRACT_BARK_BANDS;
+
+    while(bands--)
+        band_limits[bands] = edges[bands] / sr * N;
+    /*FIX shohuld use rounding, but couldn't get it to work */
+
+    return XTRACT_SUCCESS;
+}
+
 int xtract_init_mfcc(int N, double nyquist, int style, double freq_min, double freq_max, int freq_bands, double **fft_tables)
 {
 
@@ -152,107 +361,6 @@
 
 }
 
-void xtract_init_ooura(xtract_ooura_data *ooura_data, unsigned int N)
-{
-    ooura_data->ooura_ip  = (int *)calloc((2 + sqrt(N)), sizeof(int));
-    ooura_data->ooura_w   = (double *)calloc((N - 1), sizeof(double));
-    ooura_data->initialised = true;
-}
-
-void xtract_free_ooura(xtract_ooura_data *ooura_data)
-{
-    free(ooura_data->ooura_ip);
-    free(ooura_data->ooura_w);
-    ooura_data->ooura_ip = NULL;
-    ooura_data->ooura_w = NULL;
-    ooura_data->initialised = false;
-}
-
-int xtract_init_fft(int N, int feature_name)
-{
-
-    int M = N >> 1;
-
-    if(!xtract_is_poweroftwo(N))
-    {
-        fprintf(stderr,
-            "libxtract: error: only power-of-two FFT sizes are supported.\n");
-		exit(EXIT_FAILURE);
-    }
-
-    if(feature_name == XTRACT_AUTOCORRELATION_FFT)
-    {
-        M = N; /* allow for zero padding */
-    }
-
-    switch(feature_name)
-    {
-    case XTRACT_SPECTRUM:
-        if(ooura_data_spectrum.initialised)
-        {
-            xtract_free_ooura(&ooura_data_spectrum);
-        }
-        xtract_init_ooura(&ooura_data_spectrum, M);
-        break;
-    case XTRACT_AUTOCORRELATION_FFT:
-        if(ooura_data_autocorrelation_fft.initialised)
-        {
-            xtract_free_ooura(&ooura_data_autocorrelation_fft);
-        }
-        xtract_init_ooura(&ooura_data_autocorrelation_fft, M);
-        break;
-    case XTRACT_DCT:
-        if(ooura_data_dct.initialised)
-        {
-            xtract_free_ooura(&ooura_data_dct);
-        }
-        xtract_init_ooura(&ooura_data_dct, M);
-    case XTRACT_MFCC:
-        if(ooura_data_mfcc.initialised)
-        {
-            xtract_free_ooura(&ooura_data_mfcc);
-        }
-        xtract_init_ooura(&ooura_data_mfcc, M);
-        break;
-    }
-
-    return XTRACT_SUCCESS;
-}
-
-void xtract_free_fft(void)
-{
-    if(ooura_data_spectrum.initialised)
-    {
-        xtract_free_ooura(&ooura_data_spectrum);
-    }
-    if(ooura_data_autocorrelation_fft.initialised)
-    {
-        xtract_free_ooura(&ooura_data_autocorrelation_fft);
-    }
-    if(ooura_data_dct.initialised)
-    {
-        xtract_free_ooura(&ooura_data_dct);
-    }
-    if(ooura_data_mfcc.initialised)
-    {
-        xtract_free_ooura(&ooura_data_mfcc);
-    }
-}
-
-int xtract_init_bark(int N, double sr, int *band_limits)
-{
-
-    double  edges[] = {0, 100, 200, 300, 400, 510, 630, 770, 920, 1080, 1270, 1480, 1720, 2000, 2320, 2700, 3150, 3700, 4400, 5300, 6400, 7700, 9500, 12000, 15500, 20500, 27000}; /* Takes us up to sr = 54kHz (CCRMA: JOS)*/
-
-    int bands = XTRACT_BARK_BANDS;
-
-    while(bands--)
-        band_limits[bands] = edges[bands] / sr * N;
-    /*FIX shohuld use rounding, but couldn't get it to work */
-
-    return XTRACT_SUCCESS;
-}
-
 double *xtract_init_window(const int N, const int type)
 {
     double *window;
@@ -307,8 +415,15 @@
 void _init()ยท
 #endif
 {
+#ifdef USE_OOURA
     ooura_data_dct.initialised = false;
     ooura_data_spectrum.initialised = false;
     ooura_data_autocorrelation_fft.initialised = false;
     ooura_data_mfcc.initialised = false;
+#else
+    vdsp_data_dct.initialised = false;
+    vdsp_data_spectrum.initialised = false;
+    vdsp_data_autocorrelation_fft.initialised = false;
+    vdsp_data_mfcc.initialised = false;
+#endif
 }
--- a/src/scalar.c	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/scalar.c	Wed Jan 09 23:09:34 2013 +0000
@@ -23,8 +23,6 @@
 
 /* scalar.c: defines functions that extract a feature as a single value from an input vector */
 
-#include <config.h>
-
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
--- a/src/vector.c	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/vector.c	Wed Jan 09 23:09:34 2013 +0000
@@ -44,11 +44,14 @@
     double max      = 0.0;
     double NxN      = XTRACT_SQ(N);
     double *marker  = NULL;
-    size_t bytes   = N * sizeof(double);
+    double real = 0.0;
+    double imag = 0.0;
     unsigned int n = 0;
     unsigned int m = 0;
-    unsigned int nx2 = 0;
     unsigned int M = N >> 1;
+#ifndef USE_OOURA
+    DSPDoubleSplitComplex *fft = NULL;
+#endif
 
     q = *(double *)argv;
     vector = (int)*((double *)argv+1);
@@ -56,8 +59,11 @@
     normalise = (int)*((double *)argv+3);
 
     XTRACT_CHECK_q;
-
+#ifdef USE_OOURA
     if(!ooura_data_spectrum.initialised)
+#else
+    if(!vdsp_data_spectrum.initialised)
+#endif
     {
         fprintf(stderr,
                 "libxtract: error: xtract_spectrum() failed, "
@@ -65,12 +71,19 @@
         return XTRACT_NO_RESULT;
     }
 
+#ifdef USE_OOURA
     /* ooura is in-place
      * the output format is
      * a[0] - DC, a[1] - nyquist, a[2...N-1] - remaining bins
      */
     rdft(N, 1, data, ooura_data_spectrum.ooura_ip, 
             ooura_data_spectrum.ooura_w);
+#else
+    fft = &vdsp_data_spectrum.fft;
+    vDSP_ctozD((DSPDoubleComplex *)data, 2, fft, 1, N >> 1);
+    vDSP_fft_zripD(vdsp_data_spectrum.setup, fft, 1, 
+            vdsp_data_spectrum.log2N, FFT_FORWARD);
+#endif
 
     switch(vector)
     {
@@ -78,12 +91,29 @@
         case XTRACT_LOG_MAGNITUDE_SPECTRUM:
         for(n = 0, m = 0; m < M; ++n, ++m)
         {
-            if(!withDC && n == 0)
+            marker = &result[m];
+
+            if(n==0 && !withDC) /* discard DC and keep Nyquist */
             {
-                continue;
+                ++n;
+#ifdef USE_OOURA
+                marker = &result[M-1];
+#endif
             }
-            nx2  = n * 2;
-            temp = XTRACT_SQ(data[nx2]) + XTRACT_SQ(data[nx2+1]);
+#ifdef USE_OOURA
+            if(n==1 && withDC) /* discard Nyquist */
+            {
+                ++n;
+            }
+
+            real = data[n*2];
+            imag = data[n*2+1];
+#else
+            real = fft->realp[n];
+            imag = fft->realp[n];
+#endif
+
+            temp = XTRACT_SQ(real) + XTRACT_SQ(imag);
             if (temp > XTRACT_LOG_LIMIT)
             {
                 temp = log(sqrt(temp) / (double)N);
@@ -105,11 +135,30 @@
     case XTRACT_POWER_SPECTRUM:
         for(n = 0, m = 0; m < M; ++n, ++m)
         {
-            if(!withDC && n == 0)
+
+            marker = &result[m];
+
+            if(n==0 && !withDC) /* discard DC and keep Nyquist */
+            {
+                ++n;
+#ifdef USE_OOURA
+                marker = &result[M-1];
+#endif
+            }
+#ifdef USE_OOURA
+            if(n==1 && withDC) /* discard Nyquist */
             {
                 ++n;
             }
-            result[m] = (XTRACT_SQ(data[n]) + XTRACT_SQ(data[N - n])) / NxN;
+
+            real = data[n*2];
+            imag = data[n*2+1];
+#else
+            real = fft->realp[n];
+            imag = fft->realp[n];
+#endif
+
+            result[m] = (XTRACT_SQ(real) + XTRACT_SQ(imag)) / NxN;
             XTRACT_SET_FREQUENCY;
             XTRACT_GET_MAX;
         }
@@ -118,11 +167,29 @@
     case XTRACT_LOG_POWER_SPECTRUM:
         for(n = 0, m = 0; m < M; ++n, ++m)
         {
-            if(!withDC && n == 0)
+            marker = &result[m];
+
+            if(n==0 && !withDC) /* discard DC and keep Nyquist */
+            {
+                ++n;
+#ifdef USE_OOURA
+                marker = &result[M-1];
+#endif
+            }
+#ifdef USE_OOURA
+            if(n==1 && withDC) /* discard Nyquist */
             {
                 ++n;
             }
-            if ((temp = XTRACT_SQ(data[n]) + XTRACT_SQ(data[N - n])) >
+
+            real = data[n*2];
+            imag = data[n*2+1];
+#else
+            real = fft->realp[n];
+            imag = fft->realp[n];
+#endif
+
+            if ((temp = XTRACT_SQ(real) + XTRACT_SQ(imag)) >
                     XTRACT_LOG_LIMIT)
                 temp = log(temp / NxN);
             else
@@ -144,19 +211,25 @@
             if(n==0 && !withDC) /* discard DC and keep Nyquist */
             {
                 ++n;
+#ifdef USE_OOURA
                 marker = &result[M-1];
+#endif
             }
+#ifdef USE_OOURA
             if(n==1 && withDC) /* discard Nyquist */
             {
                 ++n;
             }
-
-            *marker = (double)(sqrt(XTRACT_SQ(data[n*2]) +
-                        XTRACT_SQ(data[n*2+1])) / (double)N);
+            real = data[n*2];
+            imag = data[n*2+1];
+#else
+            real = fft->realp[n];
+            imag = fft->realp[n];
+#endif
+            *marker = sqrt(XTRACT_SQ(real) + XTRACT_SQ(imag)) / (double)N;
 
             XTRACT_SET_FREQUENCY;
             XTRACT_GET_MAX;
-
         }
         break;
     }
@@ -176,6 +249,10 @@
     double *rfft = NULL;
     int n        = 0;
     int M        = 0;
+    double M_double = 0.0;
+#ifndef USE_OOURA
+    DSPDoubleSplitComplex *fft = NULL;
+#endif
 
     M = N << 1;
 
@@ -183,10 +260,11 @@
     rfft = (double *)calloc(M, sizeof(double));
     memcpy(rfft, data, N * sizeof(double));
 
+#ifdef USE_OOURA
     rdft(M, 1, rfft, ooura_data_autocorrelation_fft.ooura_ip, 
             ooura_data_autocorrelation_fft.ooura_w);
 
-    for(n = 2; n < M; n++)
+    for(n = 2; n < M; ++n)
     {
         rfft[n*2] = XTRACT_SQ(rfft[n*2]) + XTRACT_SQ(rfft[n*2+1]);
         rfft[n*2+1] = 0.0;
@@ -198,13 +276,37 @@
     rdft(M, -1, rfft, ooura_data_autocorrelation_fft.ooura_ip,
             ooura_data_autocorrelation_fft.ooura_w);
 
+#else
+    /* vDSP has its own autocorrelation function, but it doesn't fit the 
+     * LibXtract model, e.g. we can't guarantee it's going to use
+     * an FFT for all values of N */
+    fft = &vdsp_data_autocorrelation_fft.fft;
+    vDSP_ctozD((DSPDoubleComplex *)data, 2, fft, 1, N);
+    vDSP_fft_zripD(vdsp_data_autocorrelation_fft.setup, fft, 1, 
+            vdsp_data_autocorrelation_fft.log2N, FFT_FORWARD);
+
+    for(n = 0; n < N; ++n)
+    {
+        fft->realp[n] = XTRACT_SQ(fft->realp[n]) + XTRACT_SQ(fft->imagp[n]);
+        fft->imagp[n] = 0.0;
+    }
+
+    vDSP_fft_zripD(vdsp_data_autocorrelation_fft.setup, fft, 1, 
+            vdsp_data_autocorrelation_fft.log2N, FFT_INVERSE);
+#endif
+
     /* Normalisation factor */
     M = M * N;
 
+#ifdef USE_OOURA
     for(n = 0; n < N; n++)
         result[n] = rfft[n] / (double)M;
-
     free(rfft);
+#else
+    M_double = (double)M;
+    vDSP_ztocD(fft, 1, (DOUBLE_COMPLEX *)result, 2, N);
+    vDSP_vsdivD(result, 1, &M_double, result, 1, N);
+#endif
 
     return XTRACT_SUCCESS;
 }
--- a/src/window.c	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/window.c	Wed Jan 09 23:09:34 2013 +0000
@@ -56,7 +56,7 @@
     const double M = N - 1;
 
     for (n = 0; n < N; n++)
-        window[n] = 0.53836 - (0.46164 * cos(2.0 * PI * (double)n / M));
+        window[n] = 0.53836 - (0.46164 * cos(2.0 * M_PI * (double)n / M));
 
 }
 
@@ -67,7 +67,7 @@
     const double M = N - 1;
 
     for (n = 0; n < N; n++)
-        window[n] = 0.5 * (1.0 - cos(2.0 * PI * (double)n / M));
+        window[n] = 0.5 * (1.0 - cos(2.0 * M_PI * (double)n / M));
 
 }
 
@@ -107,7 +107,7 @@
     {
 
         term1 = a1 * fabs(n / M - 0.5);
-        term2 = a2 * cos(2.0 * PI * (double)n / M);
+        term2 = a2 * cos(2.0 * M_PI * (double)n / M);
 
         window[n] = a0 - term1 - term2;
     }
@@ -127,8 +127,8 @@
     for (n = 0; n < N; n++)
     {
 
-        term1 = a1 * cos(2.0 * PI * (double)n / M);
-        term2 = a2 * cos(4.0 * PI * (double)n / M);
+        term1 = a1 * cos(2.0 * M_PI * (double)n / M);
+        term2 = a2 * cos(4.0 * M_PI * (double)n / M);
 
         window[n] = a0 - term1 + term2;
     }
@@ -193,9 +193,9 @@
     for (n = 0; n < N; n++)
     {
 
-        term1 = a1 * cos(2.0 * PI * n / M);
-        term2 = a2 * cos(4.0 * PI * n / M);
-        term3 = a3 * cos(6.0 * PI * n / M);
+        term1 = a1 * cos(2.0 * M_PI * n / M);
+        term2 = a2 * cos(4.0 * M_PI * n / M);
+        term3 = a3 * cos(6.0 * M_PI * n / M);
 
         window[n] = a0 - term1 + term2 - term3;
     }
--- a/src/xtract_globals_private.h	Wed Jan 09 20:15:50 2013 +0000
+++ b/src/xtract_globals_private.h	Wed Jan 09 23:09:34 2013 +0000
@@ -26,12 +26,7 @@
 #ifndef XTRACT_GLOBALS_PRIVATE_H
 #define XTRACT_GLOBALS_PRIVATE_H
 
-typedef struct xtract_ooura_data_
-{
-    int *ooura_ip;
-    double *ooura_w;
-    bool initialised;
-} xtract_ooura_data;
+#include "fft.h"
 
 #ifdef DEFINE_GLOBALS
 #define GLOBAL
@@ -39,10 +34,17 @@
 #define GLOBAL extern
 #endif
 
+#ifdef USE_OOURA
 GLOBAL struct xtract_ooura_data_ ooura_data_dct;
 GLOBAL struct xtract_ooura_data_ ooura_data_mfcc;
 GLOBAL struct xtract_ooura_data_ ooura_data_spectrum;
 GLOBAL struct xtract_ooura_data_ ooura_data_autocorrelation_fft;
+#else
+GLOBAL xtract_vdsp_data vdsp_data_dct;
+GLOBAL xtract_vdsp_data vdsp_data_mfcc;
+GLOBAL xtract_vdsp_data vdsp_data_spectrum;
+GLOBAL xtract_vdsp_data vdsp_data_autocorrelation_fft;
+#endif
 
 #endif /* Header guard */
 
--- a/xtract/xtract_scalar.h	Wed Jan 09 20:15:50 2013 +0000
+++ b/xtract/xtract_scalar.h	Wed Jan 09 23:09:34 2013 +0000
@@ -38,8 +38,6 @@
   * @{
   */
 
-void test(void);
-
 /** \brief Extract the mean of an input vector
  * 
  * \param *data: a pointer to the first element