Function

vDSP_DFT_zop_CreateSetup

Creates a data structure for use with vDSP_DFT_Execute or vDSP_DCT_Execute to perform a complex-to-complex discrete Fourier transform, forward or inverse.

Declaration

vDSP_DFT_Setup vDSP_DFT_zop_CreateSetup(vDSP_DFT_Setup __Previous, vDSP_Length __Length, vDSP_DFT_Direction __Direction);

Parameters

__Previous

Either NULL, or a previous result from any setup function in the single-precision DFT/DCT family: vDSP_DFT_zop_CreateSetup, vDSP_DFT_zrop_CreateSetup, vDSP_DFT_CreateSetup (deprecated), or vDSP_DCT_CreateSetup.

__Length

The number of complex elements to be transformed. This length must be one of:

  • 2n

  • f * 2n, where f is 3, 5, or 15 and n is at least 3.

__Direction

The desired direction of the transform: vDSP_DFT_FORWARD or vDSP_DFT_INVERSE.

Return Value

Returns a vDSP_DFT_Setup object, or NULL if the function fails, either from lack of memory or because Length does not satisfy the requirement given above.

Discussion

This function is designed to share memory between data structures where possible. If you have an existing setup object, you should pass that object as Previous. By doing so, the returned setup object can share underlying data storage with that object. Note that this function may allocate memory; any allocated memory can ultimately be freed by vDSP_DFT_DestroySetup.

See Also

Discrete Fourier Transforms

vDSP_DFT_zop_CreateSetupD

Creates a data structure for use with vDSP_DFT_ExecuteD to perform a double-precision, complex-to-complex discrete Fourier transform, forward or inverse.

vDSP_DFT_zrop_CreateSetup

Creates a data structure for use with vDSP_DFT_Execute to perform a single-precision discrete Fourier transform, forward (real to complex) or inverse (complex to real).

vDSP_DFT_zrop_CreateSetupD

Creates a data structure for use with vDSP_DFT_ExecuteD to perform a double-precision discrete Fourier transform, forward (real to complex) or inverse (complex to real).

vDSP_DFT_DestroySetup

Releases a single-precision setup object.

vDSP_DFT_DestroySetupD

Releases a double-precision setup object.

vDSP_DFT_Execute

Calculates the discrete single-precision Fourier transform for a vector.

vDSP_DFT_ExecuteD

Calculates the discrete double-precision Fourier transform for a vector.