vDSP_zmmul

Declaration

extern void vDSP_zmmul(const DSPSplitComplex *__A, vDSP_Stride __IA, const DSPSplitComplex *__B, vDSP_Stride __IB, const DSPSplitComplex *__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

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<Float>.allocate(capacity: Int(m * p))
    _ = aReal.initialize(from: [1, 2, 3])
    
    let aImag = UnsafeMutableBufferPointer<Float>.allocate(capacity: Int(m * p))
    _ = aImag.initialize(from: [2, 3, 4])
    
    var a = DSPSplitComplex(realp: aReal.baseAddress!, imagp: aImag.baseAddress!)
    
    // `p` rows x `n` columns.
    let bReal = UnsafeMutableBufferPointer<Float>.allocate(capacity: Int(p * n))
    _ = bReal.initialize(from: [4, 5, 6])
    
    let bImag = UnsafeMutableBufferPointer<Float>.allocate(capacity: Int(p * n))
    _ = bImag.initialize(from: [5, 6, 7])
    
    var b = DSPSplitComplex(realp: bReal.baseAddress!, imagp: bImag.baseAddress!)
    
    // `m` rows x `n` columns.
    let cReal = UnsafeMutableBufferPointer<Float>.allocate(capacity: Int(m * n))
    let cImag = UnsafeMutableBufferPointer<Float>.allocate(capacity: Int(m * n))
    
    var c = DSPSplitComplex(realp: cReal.baseAddress!, imagp: cImag.baseAddress!)
    
    vDSP_zmmul(&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_zmmulD