Developer Reference

  • 2020
  • 07/15/2020
  • Public Content
Contents

DFTInit_R
,
DFTInit_C

Initializes the DFT specification structure for real and complex signals.

Syntax

Case 1: Operation on real signal
IppStatus ippsDFTInit_R_32f(int
length
, int
flag
, IppHintAlgorithm
hint
, IppsDFTSpec_R_32f*
pDFTSpec
, Ipp8u*
pMemInit
);
IppStatus ippsDFTInit_R_64f(int
length
, int
flag
, IppHintAlgorithm
hint
, IppsDFTSpec_R_64f*
pDFTSpec
, Ipp8u*
pMemInit
);
Case 2: Operation on complex signal
IppStatus ippsDFTInit_C_32fc(int
length
, int
flag
, IppHintAlgorithm
hint
, IppsDFTSpec_C_32fc*
pDFTSpec
, Ipp8u*
pMemInit
);
IppStatus ippsDFTInit_C_32f(int
length
, int
flag
, IppHintAlgorithm
hint
, IppsDFTSpec_C_32f*
pDFTSpec
, Ipp8u*
pMemInit
);
IppStatus ippsDFTInit_C_64fc(int
length
, int
flag
, IppHintAlgorithm
hint
, IppsDFTSpec_C_64fc*
pDFTSpec
, Ipp8u*
pMemInit
);
IppStatus ippsDFTInit_C_64f(int
length
, int
flag
, IppHintAlgorithm
hint
, IppsDFTSpec_C_64f*
pDFTSpec
, Ipp8u*
pMemInit
);
Include Files
ipps.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
Libraries:
ippcore.lib
,
ippvm.lib
Parameters
length
Length of the DFT transform.
flag
Specifies the result normalization method. The values for the
flag
argument are described in the section Flag and Hint Arguments.
hint
This parameter is deprecated. Set the value to
ippAlgHintNone
.
pDFTSpec
Pointer to the DFT specification structure to be initialized.
pMemInit
Pointer to the temporary work buffer.
Description
These functions initialize the DFT specification structure
pDFTSpec
with the following parameters: the transform
length
, the normalization
flag
, and the specific code
hint
. The
length
argument defines the transform length.
Before calling these functions the memory must be allocated for the DFT specification structure and the temporary work buffer (if it is required). The size of the DFT specification structure and the work buffer must be computed by the functions
ippsDFTGetSize_R
or
ippsDFTGetSize_C
.
If the work buffer is not used, the parameter
pMemInit
can be
NULL
. If the work buffer is used, the parameter
pMemInit
cannot be
NULL
. After initialization is done, the temporary work buffer can be freed.
ippsDFTInit_R
function initializes the real DFT specification structure.
ippsDFTInit_C
function initializes the complex DFT specification structure.
Application Notes
The maximum values for
length
are:
Function Flavor
Max
length
C_32fc
134217727 (2^27 - 1)
C_64fc
67108863 (2^26 - 1)
Return Values
ippStsNoErr
Indicates no error.
ippStsNullPtrErr
Indicates an error when one of the specified pointers is
NULL
.
ippStsFftFlagErr
Indicates an error when the
flag
value is incorrect.
ippStsFftOrderErr
Indicates an error when the memory needed to calculate the
length
value of the DFT transform exceeds the limit.
ippStsSizeErr
Indicates an error when
length
is less than, or equal to 0.

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