From a5b33dcab2e6218e9e17f36a26520fd1dabc58bb Mon Sep 17 00:00:00 2001
From: xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e>
Date: Fri, 8 Sep 2006 15:43:41 +0000
Subject: MAJ des tests C

git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@86 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
---
 test/c/fft.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

(limited to 'test/c/fft.c')

diff --git a/test/c/fft.c b/test/c/fft.c
index 9edf427b..1ab7b15a 100644
--- a/test/c/fft.c
+++ b/test/c/fft.c
@@ -4,6 +4,8 @@
 */
 
 #include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
 
 #ifndef PI
 #define PI  3.14159265358979323846
@@ -139,4 +141,51 @@ int dfft(double x[], double y[], int np)
   return(n);
 }
 
+/* Test harness */
 
+double * xr, * xi;
+
+int main(int argc, char ** argv)
+{
+  int n, np, npm, n2, i, j;
+  double enp, t, y, z, zr, zi, zm, a;
+  double * pxr, * pxi;
+
+  if (argc >= 2) n = atoi(argv[1]); else n = 12;
+  np = 1 << n;
+  enp = np; 
+  npm = np / 2  - 1;  
+  t = PI / enp;
+  xr = calloc(np, sizeof(double));
+  xi = calloc(np, sizeof(double));
+  pxr = xr;
+  pxi = xi;
+  *pxr = (enp - 1.0) * 0.5;
+  *pxi = 0.0;
+  n2 = np / 2;  
+  *(pxr+n2) = -0.5;
+  *(pxi+n2) =  0.0;
+  for (i = 1; i <= npm; i++) {
+    j = np - i;
+    *(pxr+i) = -0.5;
+    *(pxr+j) = -0.5;
+    z = t * (double)i;  
+    y = -0.5*(cos(z)/sin(z));
+    *(pxi+i) =  y;
+    *(pxi+j) = -y;
+  }
+  dfft(xr,xi,np);
+  zr = 0.0; 
+  zi = 0.0; 
+  npm = np-1;
+  for (i = 0; i <= npm; i++ ) {
+    a = fabs(pxr[i] - i);
+    if (zr < a) zr = a;
+    a = fabs(pxi[i]);
+    if (zi < a) zi = a;
+  }
+  zm = zr;
+  if (zr < zi) zm = zi;
+  printf("%d points, error %g\n", np, zm);
+  return 0;
+}
-- 
cgit