Subtracts a single-precision vector from the product of two single-precision vectors.


func vDSP_vmsb(_ __A: UnsafePointer<Float>, _ __IA: vDSP_Stride, _ __B: UnsafePointer<Float>, _ __IB: vDSP_Stride, _ __C: UnsafePointer<Float>, _ __IC: vDSP_Stride, _ __D: UnsafeMutablePointer<Float>, _ __ID: vDSP_Stride, _ __N: vDSP_Length)



Single-precision real input vector.


Stride for A.


Single-precision real input vector.


Stride for B.


Single-precision real input vector.


Stride for C.


Single-precision real output vector.


Stride for D.


The number of elements to process.


This function calculates the products of the first N elements of A and B, subtracts the corresponding value in C from each product, and writes the result to D:

A diagram showing the operation of the vDSP_vmsb function. There are five rows. The top two rows represents the first two inputs, vector A and vector B. The third row represents the intermediate result of the first two inputs. The forth row represents the third input, vector C. The bottom row represents the output, vector D. The diagram has connecting lines from the input vectors to the output vector indicating the relationships between the inputs and output.

The operation is:

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

The following code shows an example of using vDSP_vmsb(_:_:_:_:_:_:_:_:_:):

let stride = vDSP_Stride(1)

let a: [Float] = [10, 20, 30, 40, 50]
let b: [Float] = [ 1,  2,  3,  4,  5]

let c: [Float] = [1, 2, 3, 4, 5]

let n = vDSP_Length(a.count)

var d = [Float](repeating: 0,
                count: a.count)

vDSP_vmsb(a, stride,
         b, stride,
         c, stride,
         &d, stride,

// Prints "[9.0, 38.0, 87.0, 156.0, 245.0]"

See Also

Ternary Multiply-Subtract Operations