Hi
I'm switching my fft implementation from fftw to MKL and I'm having trouble setting up batched FFT's with varying input distance. For instance, lets say I have a float array of size [32, 320, 12], strides [1, 32, 10240] and I want to perform 1D FFT along the second dimension. Then this would be my descriptor:
DftiCreateDescriptor(&plan, DFTI_SINGLE, DFTI_COMPLEX, 1, 320);
std::vector<MKL_LONG> input_strides(4);
input_strides[0] = 0; // MKL convention
input_strides[1] = 1;
input_strides[2] = 32;
input_strides[3] = 10240;
plan_, DFTI_INPUT_STRIDES, input_strides.data());
The number of transforms (or batches) is 32*12 = 382:
DftiSetValue(plan, DFTI_NUMBER_OF_TRANSFORMS, 382);
How do I set DFTI_INPUT_DISTANCE (as required when DFTI_NUMBER_OF_TRANSFORMS > 1)?
In fftw , you specify the size and strides of all batched dimensions (howmany_dims), but MKL seems to only support a scalar distance?
In the example above, the distance varies (12 sub-batches 10240 elements apart, each with 32 FFT's of unit distance 1).
Any help is appreciated
