v?cospi

Compute the cosine of the input vector multiplied by π.

Interface Definition

C interface:

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

void vdcospi(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 vscospi Double-precision floating-point type for vdcospi	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 vscospi Double-precision floating-point type for vdcospi	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 vscospi
Double-precision floating-point type for vdcospi

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 vscospi
Double-precision floating-point type for vdcospi

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 cosine y (y = cos(x * π)) is returned for each operation value. y ∈ [-1, +1]
For special values, see the following table.
Input Value (src)

Output Value (dst)

|src| >= 0x1p24 (float)

+1

|src| >= 0x1p53 (double)

+1

±inf

nan

nan

nan

Input Value (src)	Output Value (dst)
\|src\| >= 0x1p24 (float)	+1
\|src\| >= 0x1p53 (double)	+1
±inf	nan
nan	nan

Dependencies

C: "kvml.h"

Examples

C interface:

    int i, len = 4; 
    float src[len] = {0.0f, 0.3f, INFINITY, NAN}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vscospi(len, src, dst); 
    /** 
     *  Output dst: 
     *     1.0 0.587785 nan nan 
     * 
     */

Parent topic: Function Syntax