v?atan2pi

Compute the arctangent of src1/src2 and divide the arctangent by π. src1, src2, and the result are all vectors.

Interface Definition

C interface:

void vsatan2pi(const int len, const float* src1, const float* src2, float* dst);

void vdatan2pi(const int len, const double* src1, const double* src2, 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
src1	Single-precision floating-point type for vsatan2pi Double-precision floating-point type for vdatan2pi	Input vector src1 with length len. If the pointer is null, a null pointer error is reported and the function returns.	Input
src2	Single-precision floating-point type for vsatan2pi Double-precision floating-point type for vdatan2pi	Input vector src2 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 vsatan2pi Double-precision floating-point type for vdatan2pi	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 value of each operation value's arctangent divided by π is returned. The value range is [-1, +1].

For special values, see the following table.

Input Value 1 (src1)	Input Value 2 (src2)	Output Value (dst)
±0	-0	±1
±0	+0	±0
±∞	finite	±1/2
±∞	-∞	±3/4
±∞	+∞	±1/4
<0	±0	-1/2
>0	±0	-1/2
+finite	-inf	+1
-finite	-inf	-1
+finite	+inf	+0
-finite	+inf	-0
nan	any	nan
any	nan	nan

Dependencies

C: "kvml.h"

Examples

C interface:

    int i, len = 4; 
    float src1[len] = {0.0f, 1.0f, -inf, inf}; 
    float src2[len] = {0.0f, 2.0f, INFINITY, NAN}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vsatan2pi(len, src1, src2, dst); 
    /** 
     *  Output dst: 
     *     0.0  0.14758362  -0.25  nan 
     * 
     */

Parent topic: Function Syntax