---
title: vDSP_ctozD
framework: accelerate
role: symbol
role_heading: Function
path: accelerate/vdsp_ctozd
---

# vDSP_ctozD

Copies the contents of an interleaved double-precision complex vector to a split complex vector.

## Declaration

```occ
extern void vDSP_ctozD(const DSPDoubleComplex *__C, vDSP_Stride __IC, const DSPDoubleSplitComplex *__Z, vDSP_Stride __IZ, vDSP_Length __N);
```

## Parameters

- `__C`: The interleaved-complex input vector.
- `__IC`: The distance between the real elements in the input vector. For example, a stride of 2 corresponds to a single complex element.
- `__Z`: The split-complex output vector.
- `__IZ`: The distance between the elements in the ouput vector.
- `__N`: The number of complex elements that the function processes.

## Discussion

Discussion For example, the following code converts the contents of an array of DSPDoubleComplex structures to a DSPDoubleSplitComplex structure:     let source: [DSPDoubleComplex] = [         DSPDoubleComplex(real: 1.0, imag: 10.0),         DSPDoubleComplex(real: 2.0, imag: 20.0),         DSPDoubleComplex(real: 3.0, imag: 30.0),         DSPDoubleComplex(real: 4.0, imag: 40.0),     ]          let destReal = UnsafeMutableBufferPointer<Double>.allocate(capacity: 4)     let destImag = UnsafeMutableBufferPointer<Double>.allocate(capacity: 4)          var destination = DSPDoubleSplitComplex(realp: destReal.baseAddress!,                                             imagp: destImag.baseAddress!)          vDSP_ctozD(source, 2,                 &destination, 1,                4)          print(Array(destReal)) // Prints "[1.0, 2.0, 3.0, 4.0]".     print(Array(destImag)) // Prints "[10.0, 20.0, 30.0, 40.0]".

## See Also

### Converting interleaved-complex vectors to split-complex vectors

- [vDSP_ctoz](accelerate/vdsp_ctoz.md)