Function

vDSP_dotpr_s1_15

Calculates the dot product of a fixed-point 1.15 format vector.

Declaration

void vDSP_dotpr_s1_15(const short *__A, vDSP_Stride __IA, const short *__B, vDSP_Stride __IB, short *__C, vDSP_Length __N);

Parameters

__A

Single-precision fixed-point input vector A.

__IA

The stride within vector A.

__B

Single-precision fixed-point input vector B.

__IB

The stride within vector B.

__C

Pointer to an allocated variable of type short; on return, it contains the dot product.

__N

The number of elements.

Discussion

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,
           &c,
           n)

print(c)    // Prints "141.9"

See Also

Dot Product Calculation

vDSP_dotpr

Calculates the dot product of a single-precision vector.

vDSP_dotprD

Calculates the dot product of a double-precision vector.

vDSP_dotpr_s8_24

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

vDSP_dotpr2

Calculates the dot product of a single-precision stereo vector.

vDSP_dotpr2D

Calculates the dot product of a double-precision stereo vector.

vDSP_dotpr2_s1_15

Calculates the dot product of a fixed-point 1.15 format, stereo vector.

vDSP_dotpr2_s8_24

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

vDSP_zdotpr

Calculates the complex dot product of two single-precision complex vectors.

vDSP_zdotprD

Calculates the complex dot product of two double-precision complex vectors.

vDSP_zidotpr

Calculates the inner (conjugate) product of a single-precision complex vector.

vDSP_zidotprD

Calculates the inner (conjugate) product of a double-precision complex vector.

vDSP_zrdotpr

Calculates the dot product of a single-precision complex-real vector.

vDSP_zrdotprD

Calculates the dot product of a double-precision complex-real vector.