void complex_plan_backward (complex_plan plan, double *data)
{
if (plan->bluestein)
bluestein (plan->length, data, plan->work, 1);
else
cfftb (plan->length, data, plan->work);
}
void real_plan_backward_c (real_plan plan, double *data)
{
int m;
int n=plan->length;
if (plan->bluestein)
{
data[1]=0;
for (m=2; m<n; m+=2)
{
double avg;
avg = 0.5*(data[2*n-m]+data[m]);
data[2*n-m] = data[m] = avg;
avg = 0.5*(data[2*n-m+1]-data[m+1]);
data[2*n-m+1] = avg;
data[m+1] = -avg;
}
if ((n&1)==0) data[n+1] = 0.;
bluestein (plan->length, data, plan->work, 1);
for (m=1; m<2*n; m+=2)
data[m]=0;
}
else
{
data[1] = data[0];
rfftb (n, data+1, plan->work);
for (m=n-1; m>=0; --m)
{
data[2*m] = data[m+1];
data[2*m+1] = 0.;
}
}
}
int fftLite::fft(double *realIO, double *imagIO)
{
if (N == 0)
return -1;
if (M == 0 /*(N & (N - 1)) == 0*/)
return radix2(realIO, imagIO);
else // non-power-of-two length
return bluestein(realIO, imagIO);
}
void real_plan_forward_fftpack (real_plan plan, double *data)
{
if (plan->bluestein)
{
size_t m;
size_t n=plan->length;
double *tmp = RALLOC(double,2*n);
for (m=0; m<n; ++m)
{
tmp[2*m] = data[m];
tmp[2*m+1] = 0.;
}
bluestein(n,tmp,plan->work,-1);
data[0] = tmp[0];
memcpy (data+1, tmp+2, (n-1)*sizeof(double));
DEALLOC(tmp);
}
void real_plan_forward_fftpack (real_plan plan, double *data)
{
if (plan->bluestein)
{
int m;
int n=plan->length;
double *tmp = (double *)malloc(2*n*sizeof(double));
for (m=0; m<n; ++m)
{
tmp[2*m] = data[m];
tmp[2*m+1] = 0.;
}
bluestein(n,tmp,plan->work,-1);
data[0] = tmp[0];
memcpy (data+1, tmp+2, (n-1)*sizeof(double));
free (tmp);
}
else
rfftf (plan->length, data, plan->work);
}
void real_plan_forward_c (real_plan plan, double *data)
{
int m;
int n=plan->length;
if (plan->bluestein)
{
for (m=1; m<2*n; m+=2)
data[m]=0;
bluestein (plan->length, data, plan->work, -1);
data[1]=0;
for (m=2; m<n; m+=2)
{
double avg;
avg = 0.5*(data[2*n-m]+data[m]);
data[2*n-m] = data[m] = avg;
avg = 0.5*(data[2*n-m+1]-data[m+1]);
data[2*n-m+1] = avg;
data[m+1] = -avg;
}
if ((n&1)==0) data[n+1] = 0.;
}
else
{
for (m=0; m<n; ++m) data[m+1] = data[2*m];
rfftf (n, data+1, plan->work);
data[0] = data[1];
data[1] = 0;
for (m=2; m<n; m+=2)
{
data[2*n-m] = data[m];
data[2*n-m+1] = -data[m+1];
}
if ((n&1)==0) data[n+1] = 0.;
}
}
void real_plan_backward_fftpack (real_plan plan, double *data)
{
if (plan->bluestein)
{
int m;
int n=plan->length;
double *tmp = (double *)malloc(2*n*sizeof(double));
tmp[0]=data[0];
tmp[1]=0.;
memcpy (tmp+2,data+1, (n-1)*sizeof(double));
if ((n&1)==0) tmp[n+1]=0.;
for (m=2; m<n; m+=2)
{
tmp[2*n-m]=tmp[m];
tmp[2*n-m+1]=-tmp[m+1];
}
bluestein (n, tmp, plan->work, 1);
for (m=0; m<n; ++m)
data[m] = tmp[2*m];
free (tmp);
}
else
rfftb (plan->length, data, plan->work);
}
