Function

vDSP_vsmsb(_:_:_:_:_:_:_:_:)

Multiplies the difference between a single-precision vector and a single-precision scalar value by a single-precision vector.

Declaration

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

Parameters

__A

Single-precision real input vector.

__IA

Stride for A.

__B

Pointer to single-precision real input scalar.

__C

Single-precision real input vector.

__C

Stride for C.

__D

Single-precision real output vector.

__ID

Stride for D.

__N

The number of elements to process.

Discussion

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

A diagram showing the operation of the vDSP_vsmsb function. There are five rows. The top two rows represents the first two inputs, vector A and scalar 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 - C[n];

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

let stride = vDSP_Stride(1)

let a: [Float] = [10, 20, 30, 40, 50]
var b = Float(2)

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

let n = vDSP_Length(a.count)

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

vDSP_vsmsb(a, stride,
           &b,
           c, stride,
           &d, stride,
           n)

// Prints "[19.0, 38.0, 57.0, 76.0, 95.0]"
print(d)

See Also

Ternary (Vector-Vector-Scalar) Multiply-Subtract Operations

func vDSP_vsmsbD(UnsafePointer<Double>, vDSP_Stride, UnsafePointer<Double>, UnsafePointer<Double>, vDSP_Stride, UnsafeMutablePointer<Double>, vDSP_Stride, vDSP_Length)

Multiplies the difference between a double-precision vector and a double-precision scalar value by a double-precision vector.