Developer Reference

  • 0.9
  • 09/09/2020
  • Public Content
Contents

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 one. You can set this parameter to a positive integer value using 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.
  • 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 the use 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

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

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