void cfft2(long idir, double c[], long istd, long n, long n2, double ws[])
{
long j, i0, iw3, iw2, iw1, jw, nistd;
if (n == 1) return;
iw1 = n+n;
iw2 = iw1+n+n;
iw3 = iw2+15;
istd *= 2;
nistd = istd*n;
for (; (n2--)>0 ; c+=nistd) {
if (istd > 1) {
for (i0=0 ; i0<istd ; i0+=2) {
for (j=jw=0 ; j<nistd ; j+=istd,jw+=2) {
ws[iw3+jw] = c[i0+j];
ws[iw3+1+jw] = c[1+i0+j];
}
if (idir >= 0)
cfftf1 (n,&ws[iw3],ws,&ws[iw1],(long *)&ws[iw2]);
else
cfftb1 (n,&ws[iw3],ws,&ws[iw1],(long *)&ws[iw2]);
for (j=jw=0 ; j<nistd ; j+=istd,jw+=2) {
c[i0+j] = ws[iw3+jw];
c[1+i0+j] = ws[iw3+1+jw];
}
}
} else {
if (idir >= 0)
cfftf1 (n,c,ws,&ws[iw1],(long *)&ws[iw2]);
else
cfftb1 (n,c,ws,&ws[iw1],(long *)&ws[iw2]);
}
}
return;
}
int cfftf1(int *n, double *c, double *ch, double *wa, double *ifac) {
// Casting (double*) to (int*) is dangerous if sizes differ!!!
return cfftf1(n, c, ch, wa, (int *)ifac);
}
