v?acospi

Compute the arccosine of the input vector and divide the arccosine by π.

Interface Definition

C interface:

void vsacospi(const int len, const float* src, float* dst);

void vdacospi(const int len, const double* src, double* dst);

Parameters

Parameter	Type	Description	Input/Output
len	Integer	Number of elements in the input vector. If len ≤ 0, an invalid parameter error is reported and the function returns.	Input
src	Single-precision floating-point type for vsacospi Double-precision floating-point type for vdacospi	Input vector src with length len. If the pointer is null, a null pointer error is reported and the function returns.	Input
dst	Single-precision floating-point type for vsacospi Double-precision floating-point type for vdacospi	Output vector dst with length len. If the pointer is null, a null pointer error is reported and the function returns.	Output

Parameter

Type

Description

Input/Output

len

Integer

Number of elements in the input vector.

If len ≤ 0, an invalid parameter error is reported and the function returns.

Input

src

Single-precision floating-point type for vsacospi
Double-precision floating-point type for vdacospi

Input vector src with length len.

If the pointer is null, a null pointer error is reported and the function returns.

Input

dst

Single-precision floating-point type for vsacospi
Double-precision floating-point type for vdacospi

Output vector dst with length len.

If the pointer is null, a null pointer error is reported and the function returns.

Output

Return Value

Each operation value returns the arccosine of x divided by π, that is, y = acos(x)/π. y ∈ [0, 1]
For special values, see the following table.
Input Value (src)

Output Value (dst)

1

0

-1

1.0

|x| > 1

nan

±inf

nan

nan

nan

Input Value (src)	Output Value (dst)
1	0
-1	1.0
\|x\| > 1	nan
±inf	nan
nan	nan

Dependencies

C: "kvml.h"

Examples

C interface:

    int i, len = 4; 
    float src[4] = {0.0f, 2.0f, INFINITY, NAN}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vsacospi(len, src, dst);

    printf("\n");
    /** 
     *  Output dst: 
     *     0.500000 nan nan -nan
     */

Parent topic: Function Syntax