Chris@42: /*
Chris@42:  * Copyright (c) 2003, 2007-14 Matteo Frigo
Chris@42:  * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
Chris@42:  *
Chris@42:  * This program is free software; you can redistribute it and/or modify
Chris@42:  * it under the terms of the GNU General Public License as published by
Chris@42:  * the Free Software Foundation; either version 2 of the License, or
Chris@42:  * (at your option) any later version.
Chris@42:  *
Chris@42:  * This program is distributed in the hope that it will be useful,
Chris@42:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@42:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@42:  * GNU General Public License for more details.
Chris@42:  *
Chris@42:  * You should have received a copy of the GNU General Public License
Chris@42:  * along with this program; if not, write to the Free Software
Chris@42:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Chris@42:  *
Chris@42:  */
Chris@42: 
Chris@42: 
Chris@42: #include "verify.h"
Chris@42: #include <math.h>
Chris@42: #include <stdlib.h>
Chris@42: #include <stdio.h>
Chris@42: 
Chris@42: /*
Chris@42:  * Utility functions:
Chris@42:  */
Chris@42: static double dabs(double x) { return (x < 0.0) ? -x : x; }
Chris@42: static double dmin(double x, double y) { return (x < y) ? x : y; }
Chris@42: static double norm2(double x, double y) { return dmax(dabs(x), dabs(y)); }
Chris@42: 
Chris@42: double dmax(double x, double y) { return (x > y) ? x : y; }
Chris@42: 
Chris@42: static double aerror(C *a, C *b, int n)
Chris@42: {
Chris@42:      if (n > 0) {
Chris@42: 	  /* compute the relative Linf error */
Chris@42: 	  double e = 0.0, mag = 0.0;
Chris@42: 	  int i;
Chris@42: 
Chris@42: 	  for (i = 0; i < n; ++i) {
Chris@42: 	       e = dmax(e, norm2(c_re(a[i]) - c_re(b[i]),
Chris@42: 				 c_im(a[i]) - c_im(b[i])));
Chris@42: 	       mag = dmax(mag, 
Chris@42: 			  dmin(norm2(c_re(a[i]), c_im(a[i])),
Chris@42: 			       norm2(c_re(b[i]), c_im(b[i]))));
Chris@42: 	  }
Chris@42: 	  e /= mag;
Chris@42: 
Chris@42: #ifdef HAVE_ISNAN
Chris@42: 	  BENCH_ASSERT(!isnan(e));
Chris@42: #endif
Chris@42: 	  return e;
Chris@42:      } else
Chris@42: 	  return 0.0;
Chris@42: }
Chris@42: 
Chris@42: #ifdef HAVE_DRAND48
Chris@42: #  if defined(HAVE_DECL_DRAND48) && !HAVE_DECL_DRAND48
Chris@42: extern double drand48(void);
Chris@42: #  endif
Chris@42: double mydrand(void)
Chris@42: {
Chris@42:      return drand48() - 0.5;
Chris@42: }
Chris@42: #else
Chris@42: double mydrand(void)
Chris@42: {
Chris@42:      double d = rand();
Chris@42:      return (d / (double) RAND_MAX) - 0.5;
Chris@42: }
Chris@42: #endif
Chris@42: 
Chris@42: void arand(C *a, int n)
Chris@42: {
Chris@42:      int i;
Chris@42: 
Chris@42:      /* generate random inputs */
Chris@42:      for (i = 0; i < n; ++i) {
Chris@42: 	  c_re(a[i]) = mydrand();
Chris@42: 	  c_im(a[i]) = mydrand();
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: /* make array real */
Chris@42: void mkreal(C *A, int n)
Chris@42: {
Chris@42:      int i;
Chris@42: 
Chris@42:      for (i = 0; i < n; ++i) {
Chris@42:           c_im(A[i]) = 0.0;
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: static void assign_conj(C *Ac, C *A, int rank, const bench_iodim *dim, int stride)
Chris@42: {
Chris@42:      if (rank == 0) {
Chris@42:           c_re(*Ac) = c_re(*A);
Chris@42:           c_im(*Ac) = -c_im(*A);
Chris@42:      }
Chris@42:      else {
Chris@42:           int i, n0 = dim[rank - 1].n, s = stride;
Chris@42:           rank -= 1;
Chris@42: 	  stride *= n0;
Chris@42:           assign_conj(Ac, A, rank, dim, stride);
Chris@42:           for (i = 1; i < n0; ++i)
Chris@42:                assign_conj(Ac + (n0 - i) * s, A + i * s, rank, dim, stride);
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: /* make array hermitian */
Chris@42: void mkhermitian(C *A, int rank, const bench_iodim *dim, int stride)
Chris@42: {
Chris@42:      if (rank == 0)
Chris@42:           c_im(*A) = 0.0;
Chris@42:      else {
Chris@42:           int i, n0 = dim[rank - 1].n, s = stride;
Chris@42:           rank -= 1;
Chris@42: 	  stride *= n0;
Chris@42:           mkhermitian(A, rank, dim, stride);
Chris@42:           for (i = 1; 2*i < n0; ++i)
Chris@42:                assign_conj(A + (n0 - i) * s, A + i * s, rank, dim, stride);
Chris@42:           if (2*i == n0)
Chris@42:                mkhermitian(A + i * s, rank, dim, stride);
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: void mkhermitian1(C *a, int n)
Chris@42: {
Chris@42:      bench_iodim d;
Chris@42: 
Chris@42:      d.n = n;
Chris@42:      d.is = d.os = 1;
Chris@42:      mkhermitian(a, 1, &d, 1);
Chris@42: }
Chris@42: 
Chris@42: /* C = A */
Chris@42: void acopy(C *c, C *a, int n)
Chris@42: {
Chris@42:      int i;
Chris@42: 
Chris@42:      for (i = 0; i < n; ++i) {
Chris@42: 	  c_re(c[i]) = c_re(a[i]);
Chris@42: 	  c_im(c[i]) = c_im(a[i]);
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: /* C = A + B */
Chris@42: void aadd(C *c, C *a, C *b, int n)
Chris@42: {
Chris@42:      int i;
Chris@42: 
Chris@42:      for (i = 0; i < n; ++i) {
Chris@42: 	  c_re(c[i]) = c_re(a[i]) + c_re(b[i]);
Chris@42: 	  c_im(c[i]) = c_im(a[i]) + c_im(b[i]);
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: /* C = A - B */
Chris@42: void asub(C *c, C *a, C *b, int n)
Chris@42: {
Chris@42:      int i;
Chris@42: 
Chris@42:      for (i = 0; i < n; ++i) {
Chris@42: 	  c_re(c[i]) = c_re(a[i]) - c_re(b[i]);
Chris@42: 	  c_im(c[i]) = c_im(a[i]) - c_im(b[i]);
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: /* B = rotate left A (complex) */
Chris@42: void arol(C *b, C *a, int n, int nb, int na)
Chris@42: {
Chris@42:      int i, ib, ia;
Chris@42: 
Chris@42:      for (ib = 0; ib < nb; ++ib) {
Chris@42: 	  for (i = 0; i < n - 1; ++i)
Chris@42: 	       for (ia = 0; ia < na; ++ia) {
Chris@42: 		    C *pb = b + (ib * n + i) * na + ia;
Chris@42: 		    C *pa = a + (ib * n + i + 1) * na + ia;
Chris@42: 		    c_re(*pb) = c_re(*pa);
Chris@42: 		    c_im(*pb) = c_im(*pa);
Chris@42: 	       }
Chris@42: 
Chris@42: 	  for (ia = 0; ia < na; ++ia) {
Chris@42: 	       C *pb = b + (ib * n + n - 1) * na + ia;
Chris@42: 	       C *pa = a + ib * n * na + ia;
Chris@42: 	       c_re(*pb) = c_re(*pa);
Chris@42: 	       c_im(*pb) = c_im(*pa);
Chris@42: 	  }
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: void aphase_shift(C *b, C *a, int n, int nb, int na, double sign)
Chris@42: {
Chris@42:      int j, jb, ja;
Chris@42:      trigreal twopin;
Chris@42:      twopin = K2PI / n;
Chris@42: 
Chris@42:      for (jb = 0; jb < nb; ++jb)
Chris@42: 	  for (j = 0; j < n; ++j) {
Chris@42: 	       trigreal s = sign * SIN(j * twopin);
Chris@42: 	       trigreal c = COS(j * twopin);
Chris@42: 
Chris@42: 	       for (ja = 0; ja < na; ++ja) {
Chris@42: 		    int k = (jb * n + j) * na + ja;
Chris@42: 		    c_re(b[k]) = c_re(a[k]) * c - c_im(a[k]) * s;
Chris@42: 		    c_im(b[k]) = c_re(a[k]) * s + c_im(a[k]) * c;
Chris@42: 	       }
Chris@42: 	  }
Chris@42: }
Chris@42: 
Chris@42: /* A = alpha * A  (complex, in place) */
Chris@42: void ascale(C *a, C alpha, int n)
Chris@42: {
Chris@42:      int i;
Chris@42: 
Chris@42:      for (i = 0; i < n; ++i) {
Chris@42: 	  R xr = c_re(a[i]), xi = c_im(a[i]);
Chris@42: 	  c_re(a[i]) = xr * c_re(alpha) - xi * c_im(alpha);
Chris@42: 	  c_im(a[i]) = xr * c_im(alpha) + xi * c_re(alpha);
Chris@42:      }
Chris@42: }
Chris@42: 
Chris@42: 
Chris@42: double acmp(C *a, C *b, int n, const char *test, double tol)
Chris@42: {
Chris@42:      double d = aerror(a, b, n);
Chris@42:      if (d > tol) {
Chris@42: 	  ovtpvt_err("Found relative error %e (%s)\n", d, test);
Chris@42: 
Chris@42: 	  {
Chris@42: 	       int i, N;
Chris@42: 	       N = n > 300 && verbose <= 2 ? 300 : n;
Chris@42: 	       for (i = 0; i < N; ++i) 
Chris@42: 		    ovtpvt_err("%8d %16.12f %16.12f   %16.12f %16.12f\n", i, 
Chris@42: 			       (double) c_re(a[i]), (double) c_im(a[i]),
Chris@42: 			       (double) c_re(b[i]), (double) c_im(b[i]));
Chris@42: 	  }
Chris@42: 
Chris@42: 	  bench_exit(EXIT_FAILURE);
Chris@42:      }
Chris@42:      return d;
Chris@42: }
Chris@42: 
Chris@42: 
Chris@42: /*
Chris@42:  * Implementation of the FFT tester described in
Chris@42:  *
Chris@42:  * Funda Ergün. Testing multivariate linear functions: Overcoming the
Chris@42:  * generator bottleneck. In Proceedings of the Twenty-Seventh Annual
Chris@42:  * ACM Symposium on the Theory of Computing, pages 407-416, Las Vegas,
Chris@42:  * Nevada, 29 May--1 June 1995.
Chris@42:  *
Chris@42:  * Also: F. Ergun, S. R. Kumar, and D. Sivakumar, "Self-testing without
Chris@42:  * the generator bottleneck," SIAM J. on Computing 29 (5), 1630-51 (2000).
Chris@42:  */
Chris@42: 
Chris@42: static double impulse0(dofft_closure *k,
Chris@42: 		       int n, int vecn, 
Chris@42: 		       C *inA, C *inB, C *inC,
Chris@42: 		       C *outA, C *outB, C *outC,
Chris@42: 		       C *tmp, int rounds, double tol)
Chris@42: {
Chris@42:      int N = n * vecn;
Chris@42:      double e = 0.0;
Chris@42:      int j;
Chris@42: 
Chris@42:      k->apply(k, inA, tmp);
Chris@42:      e = dmax(e, acmp(tmp, outA, N, "impulse 1", tol));
Chris@42: 
Chris@42:      for (j = 0; j < rounds; ++j) {
Chris@42: 	  arand(inB, N);
Chris@42: 	  asub(inC, inA, inB, N);
Chris@42: 	  k->apply(k, inB, outB);
Chris@42: 	  k->apply(k, inC, outC);
Chris@42: 	  aadd(tmp, outB, outC, N);
Chris@42: 	  e = dmax(e, acmp(tmp, outA, N, "impulse", tol));
Chris@42:      }
Chris@42:      return e;
Chris@42: }
Chris@42: 
Chris@42: double impulse(dofft_closure *k,
Chris@42: 	       int n, int vecn, 
Chris@42: 	       C *inA, C *inB, C *inC,
Chris@42: 	       C *outA, C *outB, C *outC,
Chris@42: 	       C *tmp, int rounds, double tol)
Chris@42: {
Chris@42:      int i, j;
Chris@42:      double e = 0.0;
Chris@42: 
Chris@42:      /* check impulsive input */
Chris@42:      for (i = 0; i < vecn; ++i) {
Chris@42: 	  R x = (sqrt(n)*(i+1)) / (double)(vecn+1);
Chris@42: 	  for (j = 0; j < n; ++j) {
Chris@42: 	       c_re(inA[j + i * n]) = 0;
Chris@42: 	       c_im(inA[j + i * n]) = 0;
Chris@42: 	       c_re(outA[j + i * n]) = x;
Chris@42: 	       c_im(outA[j + i * n]) = 0;
Chris@42: 	  }
Chris@42: 	  c_re(inA[i * n]) = x;
Chris@42: 	  c_im(inA[i * n]) = 0;
Chris@42:      }
Chris@42: 
Chris@42:      e = dmax(e, impulse0(k, n, vecn, inA, inB, inC, outA, outB, outC,
Chris@42: 			  tmp, rounds, tol));
Chris@42: 
Chris@42:      /* check constant input */
Chris@42:      for (i = 0; i < vecn; ++i) {
Chris@42: 	  R x = (i+1) / ((double)(vecn+1) * sqrt(n));
Chris@42: 	  for (j = 0; j < n; ++j) {
Chris@42: 	       c_re(inA[j + i * n]) = x;
Chris@42: 	       c_im(inA[j + i * n]) = 0;
Chris@42: 	       c_re(outA[j + i * n]) = 0;
Chris@42: 	       c_im(outA[j + i * n]) = 0;
Chris@42: 	  }
Chris@42: 	  c_re(outA[i * n]) = n * x;
Chris@42: 	  c_im(outA[i * n]) = 0;
Chris@42:      }
Chris@42: 
Chris@42:      e = dmax(e, impulse0(k, n, vecn, inA, inB, inC, outA, outB, outC,
Chris@42: 			  tmp, rounds, tol));
Chris@42:      return e;
Chris@42: }
Chris@42: 
Chris@42: double linear(dofft_closure *k, int realp,
Chris@42: 	      int n, C *inA, C *inB, C *inC, C *outA,
Chris@42: 	      C *outB, C *outC, C *tmp, int rounds, double tol)
Chris@42: {
Chris@42:      int j;
Chris@42:      double e = 0.0;
Chris@42: 
Chris@42:      for (j = 0; j < rounds; ++j) {
Chris@42: 	  C alpha, beta;
Chris@42: 	  c_re(alpha) = mydrand();
Chris@42: 	  c_im(alpha) = realp ? 0.0 : mydrand();
Chris@42: 	  c_re(beta) = mydrand();
Chris@42: 	  c_im(beta) = realp ? 0.0 : mydrand();
Chris@42: 	  arand(inA, n);
Chris@42: 	  arand(inB, n);
Chris@42: 	  k->apply(k, inA, outA);
Chris@42: 	  k->apply(k, inB, outB);
Chris@42: 
Chris@42: 	  ascale(outA, alpha, n);
Chris@42: 	  ascale(outB, beta, n);
Chris@42: 	  aadd(tmp, outA, outB, n);
Chris@42: 	  ascale(inA, alpha, n);
Chris@42: 	  ascale(inB, beta, n);
Chris@42: 	  aadd(inC, inA, inB, n);
Chris@42: 	  k->apply(k, inC, outC);
Chris@42: 
Chris@42: 	  e = dmax(e, acmp(outC, tmp, n, "linear", tol));
Chris@42:      }
Chris@42:      return e;
Chris@42: }
Chris@42: 
Chris@42: 
Chris@42: 
Chris@42: double tf_shift(dofft_closure *k,
Chris@42: 		int realp, const bench_tensor *sz,
Chris@42: 		int n, int vecn, double sign,
Chris@42: 		C *inA, C *inB, C *outA, C *outB, C *tmp,
Chris@42: 		int rounds, double tol, int which_shift)
Chris@42: {
Chris@42:      int nb, na, dim, N = n * vecn;
Chris@42:      int i, j;
Chris@42:      double e = 0.0;
Chris@42: 
Chris@42:      /* test 3: check the time-shift property */
Chris@42:      /* the paper performs more tests, but this code should be fine too */
Chris@42: 
Chris@42:      nb = 1;
Chris@42:      na = n;
Chris@42: 
Chris@42:      /* check shifts across all SZ dimensions */
Chris@42:      for (dim = 0; dim < sz->rnk; ++dim) {
Chris@42: 	  int ncur = sz->dims[dim].n;
Chris@42: 
Chris@42: 	  na /= ncur;
Chris@42: 
Chris@42: 	  for (j = 0; j < rounds; ++j) {
Chris@42: 	       arand(inA, N);
Chris@42: 
Chris@42: 	       if (which_shift == TIME_SHIFT) {
Chris@42: 		    for (i = 0; i < vecn; ++i) {
Chris@42: 			 if (realp) mkreal(inA + i * n, n);
Chris@42: 			 arol(inB + i * n, inA + i * n, ncur, nb, na);
Chris@42: 		    }
Chris@42: 		    k->apply(k, inA, outA);
Chris@42: 		    k->apply(k, inB, outB);
Chris@42: 		    for (i = 0; i < vecn; ++i) 
Chris@42: 			 aphase_shift(tmp + i * n, outB + i * n, ncur, 
Chris@42: 				      nb, na, sign);
Chris@42: 		    e = dmax(e, acmp(tmp, outA, N, "time shift", tol));
Chris@42: 	       } else {
Chris@42: 		    for (i = 0; i < vecn; ++i) {
Chris@42: 			 if (realp) 
Chris@42: 			      mkhermitian(inA + i * n, sz->rnk, sz->dims, 1);
Chris@42: 			 aphase_shift(inB + i * n, inA + i * n, ncur,
Chris@42: 				      nb, na, -sign);
Chris@42: 		    }
Chris@42: 		    k->apply(k, inA, outA);
Chris@42: 		    k->apply(k, inB, outB);
Chris@42: 		    for (i = 0; i < vecn; ++i) 
Chris@42: 			 arol(tmp + i * n, outB + i * n, ncur, nb, na);
Chris@42: 		    e = dmax(e, acmp(tmp, outA, N, "freq shift", tol));
Chris@42: 	       }
Chris@42: 	  }
Chris@42: 
Chris@42: 	  nb *= ncur;
Chris@42:      }
Chris@42:      return e;
Chris@42: }
Chris@42: 
Chris@42: 
Chris@42: void preserves_input(dofft_closure *k, aconstrain constrain,
Chris@42: 		     int n, C *inA, C *inB, C *outB, int rounds)
Chris@42: {
Chris@42:      int j;
Chris@42:      int recopy_input = k->recopy_input;
Chris@42: 
Chris@42:      k->recopy_input = 1;
Chris@42:      for (j = 0; j < rounds; ++j) {
Chris@42: 	  arand(inA, n);
Chris@42: 	  if (constrain)
Chris@42: 	       constrain(inA, n);
Chris@42: 	  
Chris@42: 	  acopy(inB, inA, n);
Chris@42: 	  k->apply(k, inB, outB);
Chris@42: 	  acmp(inB, inA, n, "preserves_input", 0.0);
Chris@42:      }
Chris@42:      k->recopy_input = recopy_input;
Chris@42: }
Chris@42: 
Chris@42: 
Chris@42: /* Make a copy of the size tensor, with the same dimensions, but with
Chris@42:    the strides corresponding to a "packed" row-major array with the
Chris@42:    given stride. */
Chris@42: bench_tensor *verify_pack(const bench_tensor *sz, int s)
Chris@42: {
Chris@42:      bench_tensor *x = tensor_copy(sz);
Chris@42:      if (BENCH_FINITE_RNK(x->rnk) && x->rnk > 0) {
Chris@42: 	  int i;
Chris@42: 	  x->dims[x->rnk - 1].is = s;
Chris@42: 	  x->dims[x->rnk - 1].os = s;
Chris@42: 	  for (i = x->rnk - 1; i > 0; --i) {
Chris@42: 	       x->dims[i - 1].is = x->dims[i].is * x->dims[i].n;
Chris@42: 	       x->dims[i - 1].os = x->dims[i].os * x->dims[i].n;
Chris@42: 	  }
Chris@42:      }
Chris@42:      return x;
Chris@42: }
Chris@42: 
Chris@42: static int all_zero(C *a, int n)
Chris@42: {
Chris@42:      int i;
Chris@42:      for (i = 0; i < n; ++i)
Chris@42: 	  if (c_re(a[i]) != 0.0 || c_im(a[i]) != 0.0)
Chris@42: 	       return 0;
Chris@42:      return 1;
Chris@42: }
Chris@42: 
Chris@42: static int one_accuracy_test(dofft_closure *k, aconstrain constrain,
Chris@42: 			     int sign, int n, C *a, C *b, 
Chris@42: 			     double t[6])
Chris@42: {
Chris@42:      double err[6];
Chris@42: 
Chris@42:      if (constrain)
Chris@42: 	  constrain(a, n);
Chris@42:      
Chris@42:      if (all_zero(a, n))
Chris@42: 	  return 0;
Chris@42:      
Chris@42:      k->apply(k, a, b);
Chris@42:      fftaccuracy(n, a, b, sign, err);
Chris@42:      
Chris@42:      t[0] += err[0];
Chris@42:      t[1] += err[1] * err[1];
Chris@42:      t[2] = dmax(t[2], err[2]);
Chris@42:      t[3] += err[3];
Chris@42:      t[4] += err[4] * err[4];
Chris@42:      t[5] = dmax(t[5], err[5]);
Chris@42: 
Chris@42:      return 1;
Chris@42: }
Chris@42: 
Chris@42: void accuracy_test(dofft_closure *k, aconstrain constrain,
Chris@42: 		   int sign, int n, C *a, C *b, int rounds, int impulse_rounds,
Chris@42: 		   double t[6])
Chris@42: {
Chris@42:      int r, i;
Chris@42:      int ntests = 0;
Chris@42:      bench_complex czero = {0, 0};
Chris@42: 
Chris@42:      for (i = 0; i < 6; ++i) t[i] = 0.0;
Chris@42: 
Chris@42:      for (r = 0; r < rounds; ++r) {
Chris@42: 	  arand(a, n);
Chris@42: 	  if (one_accuracy_test(k, constrain, sign, n, a, b, t))
Chris@42: 	       ++ntests;
Chris@42:      }
Chris@42: 
Chris@42:      /* impulses at beginning of array */
Chris@42:      for (r = 0; r < impulse_rounds; ++r) {
Chris@42: 	  if (r > n - r - 1)
Chris@42: 	       continue;
Chris@42: 	  
Chris@42: 	  caset(a, n, czero);
Chris@42: 	  c_re(a[r]) = c_im(a[r]) = 1.0;
Chris@42: 	  
Chris@42: 	  if (one_accuracy_test(k, constrain, sign, n, a, b, t))
Chris@42: 	       ++ntests;
Chris@42:      }
Chris@42:      
Chris@42:      /* impulses at end of array */
Chris@42:      for (r = 0; r < impulse_rounds; ++r) {
Chris@42: 	  if (r <= n - r - 1)
Chris@42: 	       continue;
Chris@42: 	  
Chris@42: 	  caset(a, n, czero);
Chris@42: 	  c_re(a[n - r - 1]) = c_im(a[n - r - 1]) = 1.0;
Chris@42: 	  
Chris@42: 	  if (one_accuracy_test(k, constrain, sign, n, a, b, t))
Chris@42: 	       ++ntests;
Chris@42:      }
Chris@42:      
Chris@42:      /* randomly-located impulses */
Chris@42:      for (r = 0; r < impulse_rounds; ++r) {
Chris@42: 	  caset(a, n, czero);
Chris@42: 	  i = rand() % n;
Chris@42: 	  c_re(a[i]) = c_im(a[i]) = 1.0;
Chris@42: 	  
Chris@42: 	  if (one_accuracy_test(k, constrain, sign, n, a, b, t))
Chris@42: 	       ++ntests;
Chris@42:      }
Chris@42: 
Chris@42:      t[0] /= ntests;
Chris@42:      t[1] = sqrt(t[1] / ntests);
Chris@42:      t[3] /= ntests;
Chris@42:      t[4] = sqrt(t[4] / ntests);
Chris@42: 
Chris@42:      fftaccuracy_done();
Chris@42: }