FFTW pointwise multiplication

I use FFTW to perform DFT and I have problem execute the pointwise
multiplication, here is my code 

fftw_complex * fft::multiply(fftw_complex * A, fftw_complex * B) {
fftw_complex * R;
double scale = 1.0 / (nx * ny);

R = (fftw_complex*)fftw_malloc(sizeof(fftw_complex) *nx * ny);
for(int i= 0; i < nx; i++)
for(int j= 0; j < ny/2+1; j++){
int ij = i*(ny/2+1) + j;
R[i][j].re = (A[ij].re * B[ij].re
- A[ij].im * B[ij].im) * scale;
R[i][j].im = (A[ij].re * B[ij].im
+ A[ij].im * B[ij].re) * scale;
}
return(R);
}

I receive such fault:
fft_l.C:118: request for member `re' in `*((((i * 2) + j) * 8) + R)',
which is
of non-aggregate type `double'
fft_l.C:118: request for member `re' in `*(A + (+(ij * 16)))', which is
of
non-aggregate type `double[2]'
fft_l.C:119: request for member `re' in `*(B + (+(ij * 16)))', which is
of
non-aggregate type `double[2]'
fft_l.C:119: request for member `im' in `*(A + (+(ij * 16)))', which is
of
non-aggregate type `double[2]'
pleased can you tell me what wrong with my code
Thanks

tcharles wrote:
> I use FFTW to perform DFT and I have problem execute the pointwise
> multiplication, here is my code
>
> fftw_complex * fft::multiply(fftw_complex * A, fftw_complex * B) {
> fftw_complex * R;
> double scale = 1.0 / (nx * ny);
>
> R = (fftw_complex*)fftw_malloc(sizeof(fftw_complex) *nx * ny);
> for(int i= 0; i < nx; i++)
> for(int j= 0; j < ny/2+1; j++){
> int ij = i*(ny/2+1) + j;
> R[i][j].re = (A[ij].re * B[ij].re
> - A[ij].im * B[ij].im) * scale;
> R[i][j].im = (A[ij].re * B[ij].im
> + A[ij].im * B[ij].re) * scale;
> }
> return(R);
> }
>
> I receive such fault:
> fft_l.C:118: request for member `re' in `*((((i * 2) + j) * 8) + R)',
> which is
> of non-aggregate type `double'
> fft_l.C:118: request for member `re' in `*(A + (+(ij * 16)))', which is
> of
> non-aggregate type `double[2]'
> fft_l.C:119: request for member `re' in `*(B + (+(ij * 16)))', which is
> of
> non-aggregate type `double[2]'
> fft_l.C:119: request for member `im' in `*(A + (+(ij * 16)))', which is
> of
> non-aggregate type `double[2]'
> pleased can you tell me what wrong with my code
> Thanks

The problem is that the default FFTW interface has the following
definition for the fftw_complex type:

 typedef double fftw_complex[2];

So, a fftw_complex is really just an array of two doubles, not a
structure, so you can't treat it as if it has real and imaginary part
members .re and .im. Use indices [0] and [1] instead.

http://www.fftw.org/fftw3_doc/Complex-numbers.html

Jason