vDSP_vsma

Declaration

extern void vDSP_vsma(const float *__A, vDSP_Stride __IA, const float *__B, const float *__C, vDSP_Stride __IC, float *__D, vDSP_Stride __ID, vDSP_Length __N);

Parameters

• __A:

  The input vector A in D = (A * B) + C.

• __IA:

  The distance between the elements in the input vector A.

• __B:

  The input scalar value B in D = (A * B) + C.

• __C:

  The input vector C in D = (A * B) + C.

• __IC:

  The distance between the elements in the input vector C.

• __D:

  The output vector D in D = (A * B) + C.

• __ID:

  The distance between the elements in the output vector D.

• __N:

  The number of elements that the function processes.

Discussion

This function calculates the element-wise product of vector A and scalar value B, adds vector C to the product, and writes the result to vector D.

 for (n = 0; n < N; ++n)
    D[n] = A[n] * B + C[n];

[Image]

The following code shows an example of using this function:

    let stride = 1
    let count = 5
    
    let a: [Float] = [ 1,  2,  3,  4,  5]
    let b: Float = 10
    let c: [Float] = [ 5,  4,  3,  2,  1]
    
    let d = [Float](unsafeUninitializedCapacity: count) {
        buffer, initializedCount in
        
        vDSP_vsma(a, stride,
                  [b],
                  c, stride,
                  buffer.baseAddress!, stride,
                  vDSP_Length(count))
        
        initializedCount = count
    }
    
    // Prints "[15.0, 24.0, 33.0, 42.0, 51.0]".
    print(d)

See Also

Vector-scalar-vector multiply-add operations

• vDSP_vsmaD