Function

vDSP_vsbm(_:_:_:_:_:_:_:_:_:)

Multiplies a single-precision vector by the difference of two single-precision vectors.

Declaration

func vDSP_vsbm(_ __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)

Parameters

__A

Single-precision real input vector.

__IA

Stride for A.

__B

Single-precision real input vector.

__IB

Stride for B.

__C

Single-precision real input vector.

__IC

Stride for C.

__D

Single-precision real output vector.

__ID

Stride for D.

__N

The number of elements to process.

Discussion

This function subtracts the the first N elements of A from B, multiplies the differences by the corresponding values in C, and writes the result to D:

A diagram showing the operation of the vDSP_vsbm 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_vsbm(_:_:_:_:_:_:_:_:_:):

let stride = vDSP_Stride(1)

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

let c: [Float] = [2, 0.5, 2, 0.5, 2]

let n = vDSP_Length(a.count)

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

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

// Prints "[18.0, 9.0, 54.0, 18.0, 90.0]"
print(d)

See Also

Ternary Subtract-Multiply Operations

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This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

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