Developer Reference

  • 0.10
  • 10/21/2020
  • Public Content
Contents

DFTI_FORWARD_SCALE, DFTI_BACKWARD_SCALE

The forward transform and backward transform are each associated with a scale factor
σ
of its own having the default value of 1. You can specify the scale factors using one or both of the configuration parameters
DFTI_FORWARD_SCALE
and
DFTI_BACKWARD_SCALE
. For example, for a one-dimensional transform of length
n
, you can use the default scale of 1 for the forward transform and set the scale factor for the backward transform to be 1/
n
, thus making the backward transform the inverse of the forward transform.
Set the scale factor configuration parameter using a real floating-point data type of the same precision as the value for
DFTI_PRECISION
.
For inquiry of the scale factor with the
DftiGetValue
function, the
config_val
parameter must have the same floating-point precision as the descriptor.

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.

Notice revision #20110804