Calculates the dot product of a fixed-point 8.24 format, stereo vector.


func vDSP_dotpr2_s8_24(_ __A0: UnsafePointer<Int32>, _ __IA0: vDSP_Stride, _ __A1: UnsafePointer<Int32>, _ __IA1: vDSP_Stride, _ __B: UnsafePointer<Int32>, _ __IB: vDSP_Stride, _ __C0: UnsafeMutablePointer<Int32>, _ __C1: UnsafeMutablePointer<Int32>, _ __N: vDSP_Length)



Input vector A0.


The stride within vector A0.


Input vector A1.


The stride within vector A1.


Input vector B.


The stride within vector B.


Pointer to an allocated variable of type int; on return, it contains the dot product of A0 and B.


Pointer to an allocated variable of type int; on return, it contains the dot product of A1 and B.


The number of elements.


The functions in this group calculate the dot product of two vectors, using the following operation:

C[0] = sum(A[n] * B[n], 0 <= n < N);

The following example shows how you calculate the luminosity of a color using the Rec. 709 luma coefficients for the color-to-grayscale conversion. Array a defines the color, 0xDa70D6, and array b defines the coefficients:

let a: [Float] = [0xDA, 0x70, 0xD6]
let b: [Float] = [0.2126, 0.7152, 0.0722]

Passing these values to vDSP_dotpr(_:_:_:_:_:_:) calculates the luminosity and writes the result to c:

let n = vDSP_Length(a.count)
var c: Float = .nan

let stride = vDSP_Stride(1)

vDSP_dotpr(a, stride,
           b, stride,

print(c)    // Prints "141.9"

See Also

Dot Product Calculation

static func dot<U>(U, U) -> Double

Returns the double-precision dot product of two vectors.

static func dot<U>(U, U) -> Float

Returns the single-precision dot product of two vectors.

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