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v?tan

Compute the tangent of vector elements.

Interface Definition

C interface:

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

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

Fortran interface:

CALL VSTAN(LEN, SRC, DST);

CALL VDTAN(LEN, SRC, DST);

Parameters

Parameter

Type

Description

Input/Output

len

Integer

Number of elements in the input vector.

If len ≤ 0, the system displays a message indicating that the value of len is invalid.

Input

src
  • For vstan, src is of the single-precision floating-point type.
  • For vdtan, src is of the double-precision floating-point type.

Input vector src with length len.

If the pointer is null, the system prompts a null pointer error.

Input

dst
  • For vstan, dst is of the single-precision floating-point type.
  • For vdtan, dst is of the double-precision floating-point type.

Output vector dst with length len.

If the pointer is null, the system prompts a null pointer error.

Output

Return Value

  • Each operation returns the tangent y of radian angle x. y ∈ (-INF, +INF)
  • If the input is +0, the return value is +0.
  • If the input is -0, the return value is -0.
  • If the input is ±∞, the return value is NaN.
  • If the input is NaN, the return value is NaN.
  • This function has a mathematical pole at π(1/2 + n). Because no general floating-point numbers can accurately represent the value at the pole, the return value for the pole cannot be considered reliable.

Dependencies

C: "kvml.h"

Fortran: "kvml.f03"

Examples

C interface:

    int i, len = 4; 
    float src[len] = [0.0f, 2.0f, inf, nan]; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vstan(len, src, dst); 
    /** 
     *  Output dst: 
     *     0.0  -2.185039997100830  nan  nan 
     * 
     */

Fortran interface:

    INTEGER :: LEN = 4 
    REAL(4) SRC(4)  
    REAL(4) DST(4) 
    DATA SRC /1, 2, 3, 4/ 
    CALL VSTAN(LEN, SRC, DST) 
    !  
    ! OUTPUT DST: 
    !     1.55740786, -2.18504000, -0.142546535, 1.15782118 
    !