diff dsp/transforms/FFT.cpp @ 436:2c11b8585dc2

Rename FFT back again, now we have our own project

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dsp/transforms/FFT.cpp	Mon Feb 05 17:40:13 2018 +0000
@@ -0,0 +1,202 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    QM DSP Library
+
+    Centre for Digital Music, Queen Mary, University of London.
+*/
+
+#include "FFT.h"
+
+#include "maths/MathUtilities.h"
+
+#include "kiss_fft.h"
+#include "kiss_fftr.h"
+
+#include <cmath>
+
+#include <iostream>
+
+#include <stdexcept>
+
+class FFT::D
+{
+public:
+    D(int n) : m_n(n) {
+        m_planf = kiss_fft_alloc(m_n, 0, NULL, NULL);
+        m_plani = kiss_fft_alloc(m_n, 1, NULL, NULL);
+        m_kin = new kiss_fft_cpx[m_n];
+        m_kout = new kiss_fft_cpx[m_n];
+    }
+
+    ~D() {
+        kiss_fft_free(m_planf);
+        kiss_fft_free(m_plani);
+        delete[] m_kin;
+        delete[] m_kout;
+    }
+
+    void process(bool inverse,
+                 const double *ri,
+                 const double *ii,
+                 double *ro,
+                 double *io) {
+
+        for (int i = 0; i < m_n; ++i) {
+            m_kin[i].r = ri[i];
+            m_kin[i].i = (ii ? ii[i] : 0.0);
+        }
+
+        if (!inverse) {
+
+            kiss_fft(m_planf, m_kin, m_kout);
+
+            for (int i = 0; i < m_n; ++i) {
+                ro[i] = m_kout[i].r;
+                io[i] = m_kout[i].i;
+            }
+
+        } else {
+
+            kiss_fft(m_plani, m_kin, m_kout);
+
+            double scale = 1.0 / m_n;
+
+            for (int i = 0; i < m_n; ++i) {
+                ro[i] = m_kout[i].r * scale;
+                io[i] = m_kout[i].i * scale;
+            }
+        }
+    }
+    
+private:
+    int m_n;
+    kiss_fft_cfg m_planf;
+    kiss_fft_cfg m_plani;
+    kiss_fft_cpx *m_kin;
+    kiss_fft_cpx *m_kout;
+};        
+
+FFT::FFT(int n) :
+    m_d(new D(n))
+{
+}
+
+FFT::~FFT()
+{
+    delete m_d;
+}
+
+void
+FFT::process(bool inverse,
+             const double *p_lpRealIn, const double *p_lpImagIn,
+             double *p_lpRealOut, double *p_lpImagOut)
+{
+    m_d->process(inverse,
+                 p_lpRealIn, p_lpImagIn,
+                 p_lpRealOut, p_lpImagOut);
+}
+    
+class FFTReal::D
+{
+public:
+    D(int n) : m_n(n) {
+        if (n % 2) {
+            throw std::invalid_argument
+                ("nsamples must be even in FFTReal constructor");
+        }
+        m_planf = kiss_fftr_alloc(m_n, 0, NULL, NULL);
+        m_plani = kiss_fftr_alloc(m_n, 1, NULL, NULL);
+        m_c = new kiss_fft_cpx[m_n];
+    }
+
+    ~D() {
+        kiss_fftr_free(m_planf);
+        kiss_fftr_free(m_plani);
+        delete[] m_c;
+    }
+
+    void forward(const double *ri, double *ro, double *io) {
+
+        kiss_fftr(m_planf, ri, m_c);
+
+        for (int i = 0; i <= m_n/2; ++i) {
+            ro[i] = m_c[i].r;
+            io[i] = m_c[i].i;
+        }
+
+        for (int i = 0; i + 1 < m_n/2; ++i) {
+            ro[m_n - i - 1] =  ro[i + 1];
+            io[m_n - i - 1] = -io[i + 1];
+        }
+    }
+
+    void forwardMagnitude(const double *ri, double *mo) {
+
+        double *io = new double[m_n];
+
+        forward(ri, mo, io);
+
+        for (int i = 0; i < m_n; ++i) {
+            mo[i] = sqrt(mo[i] * mo[i] + io[i] * io[i]);
+        }
+
+        delete[] io;
+    }
+
+    void inverse(const double *ri, const double *ii, double *ro) {
+
+        // kiss_fftr.h says
+        // "input freqdata has nfft/2+1 complex points"
+
+        for (int i = 0; i < m_n/2 + 1; ++i) {
+            m_c[i].r = ri[i];
+            m_c[i].i = ii[i];
+        }
+        
+        kiss_fftri(m_plani, m_c, ro);
+
+        double scale = 1.0 / m_n;
+
+        for (int i = 0; i < m_n; ++i) {
+            ro[i] *= scale;
+        }
+    }
+
+private:
+    int m_n;
+    kiss_fftr_cfg m_planf;
+    kiss_fftr_cfg m_plani;
+    kiss_fft_cpx *m_c;
+};
+
+FFTReal::FFTReal(int n) :
+    m_d(new D(n)) 
+{
+}
+
+FFTReal::~FFTReal()
+{
+    delete m_d;
+}
+
+void
+FFTReal::forward(const double *ri, double *ro, double *io)
+{
+    m_d->forward(ri, ro, io);
+}
+
+void
+FFTReal::forwardMagnitude(const double *ri, double *mo)
+{
+    m_d->forwardMagnitude(ri, mo);
+}
+
+void
+FFTReal::inverse(const double *ri, const double *ii, double *ro)
+{
+    m_d->inverse(ri, ii, ro);
+}
+
+
+