How do you use batch mode CUFFT?

Question

I am trying to figure out how to use the batch mode offered in the CUFFT library.

I basically have an image with a width of 5300 pixels and a height of 3500 pixels. Currently, this means that I am running 3500 1D FFT on those 5300 elements using FFTW.

Is this a good candidate problem to run the CUFFT library in batch mode? How to set up data to solve this problem?

thanks

Answer 1

Yes, that’s a good problem.

You should go as follows:

• create an array with the size: sizeof (cufftComplex) * 5300 * 3500 in gpu (here I assume you have complex input)
• copy your data to gpu
• create a plan using cufftPlan1d ()
• execute a plan, for example cufftExecC2C ()

For more information, you should take a look at the CUFFT Handbook.

Answer 2

Yes, you can use batch mode.

To use batch mode, items 5300 must be stored continuously.

This means that the distance between neighboring lots is 5300. You can go as follows:

.......... cufftComplex *host; cufftComplex *device; CudaMallocHost((void **)&host,sizeof(cufftComplex)*5300*3500); CudaMalloc((void **)&devcie,sizeof(cufftComplex)*5300*3500); //here add the elements,like this: //host[0-5299] the first batch, host[5300-10599] the second batch ,and up to the 3500th batch. CudaMemcpy(device,host,sizeof(cufftComplex)*5300*3500,......); CufftPlan1d(&device,5300,type,3500); CufftExecC2C(......); ...... 

See the CUFFT Handbook for more information.