# vDSP_ztocD Copies the contents of a split double-precision complex vector to an interleaved vector. ``` extern void vDSP_ztocD(const DSPDoubleSplitComplex *__Z, vDSP_Stride __IZ, DSPDoubleComplex *__C, vDSP_Stride __IC, vDSP_Length __N); ``` ## Parameters `__Z` The split-complex input vector. `__IZ` The distance between the elements in the input vector. `__C` The interleaved-complex output vector. `__IC` The distance between the real elements in the output vector. For example, a stride of `2` corresponds to a single complex element. `__N` The number of complex elements that the function processes. ## Discussion For example, the following code converts the contents of a [`DSPDoubleSplitComplex`](/documentation/Accelerate/DSPDoubleSplitComplex) structure to an array of [`DSPDoubleComplex`](/documentation/Accelerate/DSPDoubleComplex) structures : ```swift let srcReal = UnsafeMutableBufferPointer.allocate(capacity: 4) _ = srcReal.initialize(from: [1.0, 2.0, 3.0, 4.0]) let srcImag = UnsafeMutableBufferPointer.allocate(capacity: 4) _ = srcImag.initialize(from: [10.0, 20.0, 30.0, 40.0]) var source = DSPDoubleSplitComplex(realp: srcReal.baseAddress!, imagp: srcImag.baseAddress!) let destination = [DSPDoubleComplex](unsafeUninitializedCapacity: 4) { buffer, initializedCount in vDSP_ztocD(&source, 1, buffer.baseAddress!, 2, 4) initializedCount = 4 } // Prints: // "[ DSPComplex(real: 1.0, imag: 10.0), // DSPComplex(real: 2.0, imag: 20.0), // DSPComplex(real: 3.0, imag: 30.0), // DSPComplex(real: 4.0, imag: 40.0) ]". print(destination) ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)