I've included published code by Paul Bourke that fails to compile. The
error message is as attached in the .jpg file. I have upgraded though 3
versions of DevC++ - all that changed is the text of the error message.
The offending lines are highlighted.
Dev-C++ 4.9.9.2
XP, Win 2000, NT 4.0
Any help would be appreciated.
Thanks in advance,
Robert
-----------------------------------------------------------------
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cmath>
using namespace std;
typedef struct
{
double real;
double imag;
}
COMPLEX; // complex
// FFT & 2DFFT code written by Paul Bourke July 1998
/*----------------------------------------------------------------------
---
Calculate the closest but lower power of two of a number
twopm = 2**m <= n
Return TRUE if 2**m == n
*/
int Powerof2( int n, int *m, int *twopm ) {
if ( n <= 1 )
{
*m = 0;
*twopm = 1;
return false;
}
*m = 1;
*twopm = 2;
do
{
(*m)++;
(*twopm) *= 2;
} while ( 2 * (*twopm) <= n );
if ( *twopm != n )
{
return false;
}
else
{
return true;
}
}
/*----------------------------------------------------------------------
---
This computes an in-place complex-to-complex FFT
x and y are the real and imaginary arrays of 2^m points.
dir = 1 gives forward transform
dir = -1 gives reverse transform
Formula: forward
N-1
---
1 \ - j k 2 pi n / N
X(n) = --- > x(k) e = forward transform
N / n=0..N-1
---
k=0
Formula: reverse
N-1
---
\ j k 2 pi n / N
X(n) = > x(k) e = forward transform
/ n=0..N-1
---
k=0
*/
int FFT (int dir, int m, double *x, double *y) {
long nn,i,i1,j,k,i2,l,l1,l2;
double c1,c2,tx,ty,t1,t2,u1,u2,z;
/* Calculate the number of points */
nn = 1;
for (i=0;i<m;i++)
nn *= 2;
/* Do the bit reversal */
i2 = nn >> 1;
j = 0;
for (i=0;i<nn-1;i++) {
if (i < j) {
tx = x[i];
ty = y[i];
x[i] = x[j];
y[i] = y[j];
x[j] = tx;
y[j] = ty;
}
k = i2;
while (k <= j) {
j -= k;
k >>= 1;
}
j += k;
}
/* Compute the FFT */
c1 = -1.0;
c2 = 0.0;
l2 = 1;
for (l=0;l<m;l++) {
l1 = l2;
l2 <<= 1;
u1 = 1.0;
u2 = 0.0;
for (j=0;j<l1;j++) {
for (i=j;i<nn;i+=l2) {
i1 = i + l1;
t1 = u1 * x[i1] - u2 * y[i1];
t2 = u1 * y[i1] + u2 * x[i1];
x[i1] = x[i] - t1;
y[i1] = y[i] - t2;
x[i] += t1;
y[i] += t2;
}
z = u1 * c1 - u2 * c2;
u2 = u1 * c2 + u2 * c1;
u1 = z;
}
c2 = sqrt((1.0 - c1) / 2.0);
if (dir == 1)
c2 = -c2;
c1 = sqrt((1.0 + c1) / 2.0);
}
/* Scaling for forward transform */
if (dir == 1) {
for (i=0;i<nn;i++) {
x[i] /= (double)nn;
y[i] /= (double)nn;
}
}
return true;
}
/*----------------------------------------------------------------------
---
Perform a 2D FFT inplace given a complex 2D array
The direction dir, 1 for forward, -1 for reverse
The size of the array (nx,ny)
Return false if there are memory problems or
the dimensions are not powers of 2 */
int FFT2D(COMPLEX **c, int nx, int ny, int dir) {
int i = 0, j = 0;
int m = 0, twopm = 0;
double *real,*imag;
/* Transform the rows */
real = (double *)malloc(nx * sizeof(double));
imag = (double *)malloc(nx * sizeof(double));
if (real == NULL || imag == NULL)
{
return false;
}
if (!Powerof2(nx,&m,&twopm) || twopm != nx)
{
return false;
}
for (j=0;j<ny;j++)
{
for (i=0;i<nx;i++)
{
real[i] = c[i][j].real;
imag[i] = c[i][j].imag;
}
FFT (int dir, int m, double real, double imag);
for (i=0;i<nx;i++)
{
c[i][j].real = real[i];
c[i][j].imag = imag[i];
}
}
free(real);
free(imag);
/* Transform the columns */
real = (double *)malloc(ny * sizeof(double));
imag = (double *)malloc(ny * sizeof(double));
if (real == NULL || imag == NULL)
return false;
if (!Powerof2(ny,&m,&twopm) || twopm != ny)
return false;
for (i=0;i<nx;i++)
{
for (j=0;j<ny;j++)
{
real[j] = c[i][j].real;
imag[j] = c[i][j].imag;
}
FFT (int dir, int m, double real, double imag);
for (j=0;j<ny;j++)
{
c[i][j].real = real[j];
c[i][j].imag = imag[j];
}
}
free(real);
free(imag);
return true;
}
int main ()
{
{ //use this section to hold DOS window at end of execution
// must be located at end of main!
printf("\n");
printf("\n*** execution has completed sucessfully ***\n");
// user_wait();
<<devcpperror.jpg>> return 0;
}
}
Classification: UNCLASSIFIED
Caveats: NONE
Attachment:
devcpperror.jpg
Description: devcpperror.jpg
