Mercurial > pygar

     1 #include <stdio.h>

     2 #include <stdlib.h>

     3 #include <math.h>

     4 

     5 

     6 int DFT(int dir,int m,double *x1,double *y1)

     7 {

     8    long i,k;

     9    double arg;

    10    double cosarg,sinarg;

    11    double *x2=NULL,*y2=NULL;

    12 

    13    x2 = (double *)(malloc(m*sizeof(double)));

    14    y2 = (double *)(malloc(m*sizeof(double)));

    15    if (x2 == NULL || y2 == NULL)

    16       return 0;

    17 

    18    for (i=0;i<m;i++) {

    19       x2[i] = 0;

    20       y2[i] = 0;

    21       arg = - dir * 2.0 * 3.141592654 * (double)i / (double)m;

    22       for (k=0;k<m;k++) {

    23          cosarg = cos(k * arg);

    24          sinarg = sin(k * arg);

    25          x2[i] += (x1[k] * cosarg - y1[k] * sinarg);

    26          y2[i] += (x1[k] * sinarg + y1[k] * cosarg);

    27       }

    28    }

    29 

    30    /* Copy the data back */

    31    if (dir == 1) {

    32       for (i=0;i<m;i++) {

    33          x1[i] = x2[i];

    34          y1[i] = y2[i];

    35       }

    36    } else {

    37       for (i=0;i<m;i++) {

    38          x1[i] = x2[i];

    39          y1[i] = y2[i];

    40       }

    41    }

    42 

    43    free(x2);

    44    free(y2);

    45    return 1;

    46 }
author	rlm
date	Wed, 28 Apr 2010 08:19:09 -0400
parents	74716e9a81cc
children