Contents

subtract(multiplication:_:result:)

Calculates the double-precision element-wise difference of the product of a vector and a scalar value, and a vector.

Declaration

static func subtract<T, U, V>(multiplication: (a: U, b: Double), _ vector: T, result: inout V) where T : AccelerateBuffer, U : AccelerateBuffer, V : AccelerateMutableBuffer, T.Element == Double, U.Element == Double, V.Element == Double

Parameters

  • multiplication:

    A tuple that contains the vectors A and B in D = (A * B) - C.

  • vector:

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

  • result:

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

Discussion

This function calculates the element-wise product of vector A and scalar value B, subtracts vector C from 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 count = 5
    
    let a: [Double] = [ 1,  2,  3,  4,  5]
    let b: Double = 10
    let c: [Double] = [ 5,  4,  3,  2,  1]
    
    let d = [Double](unsafeUninitializedCapacity: count) {
        buffer, initializedCount in
        
        vDSP.subtract(multiplication: (a, b),
                      c,
                      result: &buffer)
        
        initializedCount = count
    }
    
    // Prints "[5.0, 16.0, 27.0, 38.0, 49.0]".
    print(d)

See Also

Subtraction