Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 12/16/2022
Public

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DFTI_NUMBER_OF_TRANSFORMS

If you need to perform a large number of identical FFTs, you can do this in a single call to a DftiCompute* function with the value of the DFTI_NUMBER_OF_TRANSFORMS configuration parameter equal to the actual number of the transforms. The default value of this parameter is 1. You can set this parameter to a positive integer value of the MKL_LONG data type. When setting the number of transforms to a value greater than one, you also need to specify the distance between the input data sets and the distance between the output data sets using one of the DFTI_INPUT_DISTANCE and DFTI_OUTPUT_DISTANCE configuration parameters or both.

IMPORTANT:
  • The data sets to be transformed must not have common elements.

  • All the sets of data must be located within the same memory block.

To better understand usage of the DFTI_NUMBER_OF_TRANSFORMS configuration parameter, see this example in your Intel® oneAPI Math Kernel Library directory:

./examples/dftc/source/config_number_of_transforms.c