v?sqrt

Interface Definition

C interface:

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

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

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

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

Fortran interface:

CALL VSSQRT(LEN, SRC, DST);

CALL VDSQRT(LEN, SRC, DST);

Parameters

Return Value

• The square root of a number is returned for each operation value. The value range is [0, +INF).
• For vssqrt and vdsqrt, special output values are listed in the following table.

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

• For vcsqrt and vzsqrt, the Euler formula and double angle formulas of trigonometric functions are used.

  , where .

  The following table lists the special values.

  RE(z) i * IM(z)	-∞	-X	-0	+0	+X	+∞	NAN
  +i * ∞	+∞+i*∞	+∞+i*∞	+∞+i*∞	+∞+i*∞	+∞+i*∞	+∞+i*∞	+∞+i*∞
  +i * Y	+0+i*∞					+∞+i*0	QNAN+i*QNAN
  +i * 0	+0+i*∞		+0+i*0	+0+i*0		+∞+i*0	QNAN+i*QNAN
  -i * 0	+0-i*∞		+0+i*0	+0+i*0		+∞-i*0	QNAN+i*QNAN
  -i * Y	+0-i*∞					+∞-i*0	QNAN+i*QNAN
  -i * ∞	+∞-i*∞	+∞-i*∞	+∞-i*∞	+∞-i*∞	+∞-i*∞	+∞-i*∞	+∞-i*∞
  +i * NAN	QNAN+i*∞	QNAN+i*QNAN	QNAN+i*QNAN	QNAN+i*QNAN	QNAN+i*QNAN	+∞+i*QNAN	QNAN+i*QNAN

Dependencies

C: "kvml.h"

Fortran: "kvml.f03"

Examples

C interface:

    int i, len = 4; 
    float src[len] = {0.0f, 0.25f, 16.0f, 1.0f}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vssqrt(len, src, dst); 
    /** 
     *  Output dst: 
     *     0.0  0.5  4.0  1.0 
     * 
     */

Fortran interface:

    INTEGER :: LEN = 4 
    REAL(4) SRC(4)  
    REAL(4) DST(4) 
    DATA SRC /1, 2, 3, 4/ 
    CALL VSSQRT(LEN, SRC1, SRC2, DST) 
    !  
    ! OUTPUT DST: 
    !     1.000000000, 1.414213538, 1.732050776, 2.000000000 
    !