---
title: vDSP_zmmulD
framework: accelerate
role: symbol
role_heading: Function
path: accelerate/vdsp_zmmuld
---

# vDSP_zmmulD

Performs an out-of-place multiplication of two double-precision complex matrices.

## Declaration

```occ
extern void vDSP_zmmulD(const DSPDoubleSplitComplex *__A, vDSP_Stride __IA, const DSPDoubleSplitComplex *__B, vDSP_Stride __IB, const DSPDoubleSplitComplex *__C, vDSP_Stride __IC, vDSP_Length __M, vDSP_Length __N, vDSP_Length __P);
```

## Parameters

- `__A`: The M x P left-hand side input matrix.
- `__IA`: The distance between the elements in the left-hand side input matrix.
- `__B`: The P x N right-hand side input matrix.
- `__IB`: The distance between the elements in the right-hand side input matrix.
- `__C`: The M x N output matrix.
- `__IC`: The distance between the elements in the output matrix.
- `__M`: The number of rows in matrices A and C.
- `__N`: The number of columns in matrices B and C.
- `__P`: The number of columns in matrix A and the number of rows in matrix B.

## Discussion

Discussion The following code multiplies the matrices a and b, and writes the result to matrix c:     //                        [ 4+5i,     // [ 1+2i, 2+3i, 3+4i ] *   5+6i,  = [ -24+85i ]     //                          6+7i ]          let m: vDSP_Length = 1     let n: vDSP_Length = 1     let p: vDSP_Length = 3          // `m` rows x `p` columns.     let aReal = UnsafeMutableBufferPointer<Double>.allocate(capacity: Int(m * p))     _ = aReal.initialize(from: [1, 2, 3])          let aImag = UnsafeMutableBufferPointer<Double>.allocate(capacity: Int(m * p))     _ = aImag.initialize(from: [2, 3, 4])          var a = DSPDoubleSplitComplex(realp: aReal.baseAddress!,                                   imagp: aImag.baseAddress!)          // `p` rows x `n` columns.     let bReal = UnsafeMutableBufferPointer<Double>.allocate(capacity: Int(p * n))     _ = bReal.initialize(from: [4, 5, 6])          let bImag = UnsafeMutableBufferPointer<Double>.allocate(capacity: Int(p * n))     _ = bImag.initialize(from: [5, 6, 7])          var b = DSPDoubleSplitComplex(realp: bReal.baseAddress!,                                   imagp: bImag.baseAddress!)          // `m` rows x `n` columns.     let cReal = UnsafeMutableBufferPointer<Double>.allocate(capacity: Int(m * n))     let cImag = UnsafeMutableBufferPointer<Double>.allocate(capacity: Int(m * n))          var c = DSPDoubleSplitComplex(realp: cReal.baseAddress!,                                   imagp: cImag.baseAddress!)          vDSP_zmmulD(&a, 1,                 &b, 1,                 &c, 1,                 m, n, p)          print(Array(cReal)) // Prints "[-24.0]".     print(Array(cImag)) // Prints "[85.0]".

## See Also

### Multiplying complex matrices

- [vDSP_zmmul](accelerate/vdsp_zmmul.md)