init(previousDFT:count:direction:transformType:ofType:)

Declaration

init(previousDFT: vDSP.DiscreteFourierTransform<T>?, count: Int, direction: vDSP.FourierTransformDirection, transformType: vDSP.DFTTransformType, ofType: T.Type) throws

Parameters

• previousDFT:

  A previous DFT instance to share data with.

• count:

  The number of complex elements.

• transformType:

  Specifies whether the forward transform is real-to-complex or complex-to-complex.

Discussion

The count parameter must be:

• For split-complex real-to-complex: 2ⁿ or f * 2ⁿ, where f is 3, 5, or 15 and n >= 4.

• For split-complex complex-to-complex: 2ⁿ or f * 2ⁿ, where f is 3, 5, or 15 and n >= 3.

• For interleaved: f * 2ⁿ, where f is 2, 3, 5, 3x3, 3x5, or 5x5, and n>=2.