problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLACE

ringlery — Tue, 02 Dec 2008 22:55:56 GMT

Greetings,

I have an array which contains evenly spaced data for multiple FFT's. The FFT yields the proper results as long as the results are placed in the original array. If I change the DFTI_PLACEMENT value to DFTI_NOT_INPLACE then only the first FFT is calculated and placed in the new array. Here's the code which performs the FFT:

DFTI_DESCRIPTOR *handle;

long status;

int mult = nz;

status = DftiCreateDescriptor(&handle, DFTI_DOUBLE, DFTI_COMPLEX,1, ntheta);

status = DftiSetValue(handle, DFTI_PLACEMENT, DFTI_NOT_INPLACE);

status = DftiSetValue(handle, DFTI_FORWARD_SCALE, 1./double(ntheta));

status = DftiSetValue(handle, DFTI_NUMBER_OF_TRANSFORMS, nz);

status = DftiSetValue(handle, DFTI_INPUT_DISTANCE, ntheta);

status = DftiCommitDescriptor(handle);

status = DftiComputeForward(handle, sidewall,fftsidewall);

status = DftiFreeDescriptor(&handle);

Any assistance would be appreciated. I should also mention that I'm running this on an OSX 10.5.5 machine and using the MKL which comes with the 11.0.056 intel c++ compiler. I'm using the 64-bit libraries, and they have been dynamically linked.

Re: problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLAC

Dmitry_B_Intel — Wed, 03 Dec 2008 12:12:31 GMT

Perhaps, adding DftiSetValue(handle,DFTI_OUTPUT_DISTANCE,ntheta) will help.

Dima

Re: problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLAC

ringlery — Wed, 03 Dec 2008 18:46:45 GMT

Quoting - Dmitry Baksheev (Intel)

Perhaps, adding DftiSetValue(handle,DFTI_OUTPUT_DISTANCE,ntheta) will help.

Dima

Yup, that worked perfectly. Thanks for your help!

topic problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLACE in Intel® oneAPI Math Kernel Library

problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLACE

Re: problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLAC

Re: problem with multiple FFT when DFTI_PLACEMENT is NOT_INPLAC