v?atanpi

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

Interface Definition

C interface:

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

void vdatanpi(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 vsatanpi Double-precision floating-point type for vdatanpi	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 vsatanpi Double-precision floating-point type for vdatanpi	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 vsatanpi
Double-precision floating-point type for vdatanpi

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 vsatanpi
Double-precision floating-point type for vdatanpi

Output vector dst with length len.

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

Output

Return Value

The result y is returned according to the formula: y = arctan(x)/π. y ∈ (-1/2, +1/2)
For special values, see the following table.
Input Value (src)

Output Value (dst)

+0

+0

-0

-0

±inf

±0.5

nan

nan

Input Value (src)	Output Value (dst)
+0	+0
-0	-0
±inf	±0.5
nan	nan

Dependencies

C: "kvml.h"

Examples

C interface:

    int i, len = 4; 
    float src[len] = {0.0f, 2.0f, INFINITY, NAN}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vsatanpi(len, src, dst); 
    /** 
     *  Output dst: 
     *     0.0  0.3524164  0.5  nan 
     * 
     */

Parent topic: Function Syntax