vDSP_maxmgv

Declaration

void vDSP_maxmgv(const float *__A, vDSP_Stride __IA, float *__C, vDSP_Length __N);

Parameters

• __A:

  The single-precision real input vector A.

• __I:

  The stride for input vector A.

• __C:

  The single-precsion output scalar.

• __N:

  The number of elements to process. If N is zero (0), this function returns -INFINITY.

Discussion

This function calculates the maximum magnitude of the first N elements of A and writes the result to C:

[Image]

The operation is:

*C = -INFINITY;
for (n = 0; n < N; ++n)
    if (*C < |A[n*I]|)
        *C = |A[n*I]|;

The following code shows an example of using vDSP_maxmgv.

let stride = vDSP_Stride(1)

let a: [Float] = [-1.5, 2.25, 3.6,
                  0.2, -0.1, -4.3]
let n = vDSP_Length(a.count)

var c: Float = .nan

vDSP_maxmgv(a,
            stride,
            &c,
            n)

print("max magnitude", c) // Prints "max magnitude 4.3".