(Q) CUFFT, how to use cufft function.. CUFFT

Accelerated Computing CUDA CUDA Programming and Performance
1

hello,

I have a question on cufft.
now, I use cufft. It is my first time.

there are some cufft functions in cufft.h. For example, cufftPlan2d, cufftExecC2C…
Can I use them at global??

I can use them at main…I want to use them at global.

thanks.

2

I don’t think you can do what you are asking about. All those functions are host side functions, intended to be called by the host cpu only.

3

Thank you for your reply.

is there any method to use them at global??
I want to calculate some processes in gpu without cudaMemcpy.

global_ void fft_Cal(Complex *input_A, Complex input_B…)
{
ifft~~;
normalization;
A=absphase;
fft;

}

4

It is a fundamental feature of CUDA that kernels (what you are calling global functions) can’t call other kernels, so no.

5

it’s impossible to call cufft functions from inside kernels.

But you can split the kernel into a few parts, like

global_ void fft_Cal_1(Complex *input_A, Complex input_B…)
{
normalization;
A=absphase;
}

and call

fft;
fft_Cal_1;
ifft;