v?sub

Perform element-wise subtraction of vectors. The difference is also a vector.

Interface Definition

C interface:

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

void vdsub(const int len, const double* src1, const double* src2, double* dst);

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

void vzsub(const int len, const double complex *src1, const double complex *src2, double complex *dst)

Fortran interface:

CALL VSSUB(LEN, SRC1, SRC2, DST);

CALL VDSUB(LEN, SRC1, SRC2, DST);

CALL VCSUB(LEN, SRC1, SRC2, DST);

CALL VZSUB(LEN, SRC1, SRC2, 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
src1	For vssub, src1 is of single-precision floating-point type. For vdsub, src1 is of double-precision floating-point type. For vcsub, src1 is of single-precision floating-point complex number type. For vzsub, src1 is of double-precision floating-point complex number type.	Input vector src1 (minuend) with length len. If the pointer is null, the system prompts a null pointer error.	Input
src2	For vssub, src2 is of single-precision floating-point type. For vdsub, src2 is of double-precision floating-point type. For vcsub, src2 is of single-precision floating-point complex number type. For vzsub, src2 is of double-precision floating-point complex number type.	Input vector src2 (subtrahend) with length len. If the pointer is null, the system prompts a null pointer error.	Input
dst	For vssub, dst is of single-precision floating-point type. For vdsub, dst is of double-precision floating-point type. For vcsub, dst is of single-precision floating-point complex number type. For vzsub, dst is of double-precision floating-point complex number type.	Output vector dst with length len. If the pointer is null, the system prompts a null pointer error.	Output

Return Value

The difference of two numbers is returned for each operation value. The value range is (-INF, +INF).
If the value of src1 is –0 and the value of src2 is +0, then the value of dst is –0. If the value of src1 is ±0 and the value of src2 is ±0, then the value of dst is +0.
If the value of src1 is -∞ and the value of src2 is -∞, then the value of dst is NaN. If the value of src1 is +∞ and the value of src2 is +∞, then the value of dst is NaN.
If the value of src1 is +∞ and the value of src2 is -∞, then the value of dst is +∞. If the value of src1 is -∞ and the value of src2 is +∞, then the value of dst is -∞.
If the value of src1 or src2 is NaN, the value of dst is NaN.

Dependencies

C: "kvml.h"

Fortran: "kvml.f03"

Examples

C interface:

    int i, len = 4; 
    float src1[len] = {0.3f, 0.7f, 2.5f, 10.0f}; 
    float src2[len] = {0.0f, 0.5f, 1.5f, 5.5f}; 
    float* dst = (float*)malloc(sizeof(float) * len); 
    if (dst == NULL) { 
        printf("Malloc Failed!\n"); 
        return 0; 
    } 
    vssub(len, src1, src2, dst); 
    /** 
     *  Output dst: 
     *     0.3  0.2  1.0  4.5 
     * 
     */

Fortran interface:

    INTEGER :: LEN = 4 
    REAL(4) SRC1(4)  
    REAL(4) SRC2(4) 
    REAL(4) DST(4) 
    DATA SRC1 /1.2, 2.5, -2.4, 3.6/ 
    DATA SRC2 /8.6, -2.5, -12.4, 32.6/ 
    CALL VSSUB(LEN, SRC1, SRC2, DST) 
    ! 
    ! OUTPUT DST 
    !     -7.400000572, 5.000000000, 10.000000000, -28.999998093 
    !

Parent topic: Function Syntax