Intel® Integrated Performance Primitives (Intel® IPP) Developer Guide and Reference
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DFTGetSize_R, DFTGetSize_C
Computes sizes of the DFT work buffer and required working buffers.
Syntax
Case 1: Operation on real signal
IppStatus ippsDFTGetSize_R_32f(int length, int flag, IppHintAlgorithm hint, int* pSizeSpec, int* pSizeInit, int* pSizeBuf);
IppStatus ippsDFTGetSize_R_64f(int length, int flag, IppHintAlgorithm hint, int* pSizeSpec, int* pSizeInit, int* pSizeBuf);
Case 2: Operation on complex signal
IppStatus ippsDFTGetSize_C_32fc(int length, int flag, IppHintAlgorithm hint, int* pSizeSpec, int* pSizeInit, int* pSizeBuf);
IppStatus ippsDFTGetSize_C_32f(int length, int flag, IppHintAlgorithm hint, int* pSizeSpec, int* pSizeInit, int* pSizeBuf);
IppStatus ippsDFTGetSize_C_64fc(int length, int flag, IppHintAlgorithm hint, int* pSizeSpec, int* pSizeInit, int* pSizeBuf);
IppStatus ippsDFTGetSize_C_64f(int length, int flag, IppHintAlgorithm hint, int* pSizeSpec, int* pSizeInit, int* pSizeBuf);
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. | 
| pSizeSpec | Pointer to the DFT specification structure size value. | 
| pSizeInit | Pointer to the buffer size value for DFT initialization functions. | 
| pSizeBuf | Pointer to the size value of the DFT external work buffer. | 
Description
These functions compute the size of DFT specification structure, the work buffer size for the DFT structure initialization functions ippsDFTInit_R and ippsDFTInit_C, and size of the DFT work buffer for different flavors of ippsDFTFwd and ippsDFTInv. Their values in bytes are stored in pSpecSize, pSizeInit, and pSizeBuf respectively.
ippsDFTGetSize_R function is used for real flavors of the DFT functions.
ippsDFTGetSize_C function is used for complex flavors of the DFT functions.
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. |