Developer Reference

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

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.