?axpby

Add the products of two scaled vectors, that is, $\text{[math]}$ .

alpha and beta are multiplication coefficients, and x and y are vectors with a length of n.

Interface Definition

C interface:

void cblas_saxpby(const BLASINT n, const float alpha, const float *x, const BLASINT incx, const float beta, float *y, const BLASINT incy);

void cblas_daxpby(const BLASINT n, const double alpha, const double *x, const BLASINT incx, const double beta, double *y, const BLASINT incy);

void cblas_caxpby(const BLASINT n, const void *alpha, const void *x, const BLASINT incx, const void *beta, void *y, const BLASINT incy);

void cblas_zaxpby(const BLASINT n, const void *alpha, const void *x, const BLASINT incx, const void *beta, void *y, const BLASINT incy);

Fortran interface:

CALL SAXPBY(N, ALPHA, X, INCX, BETA, Y, INCY)

CALL DAXPBY(N, ALPHA, X, INCX, BETA, Y, INCY)

CALL CAXPBY(N, ALPHA, X, INCX, BETA, Y, INCY)

CALL ZAXPBY(N, ALPHA, X, INCX, BETA, Y, INCY)

Parameters

Parameter	Type	Description	Input/Output
n	Integer	Number of elements in the x vector	Input
alpha	Double-precision floating-point type for daxpby Single-precision floating-point type for saxpby Single-precision complex number type for caxpby Double-precision complex number type for zaxpby	Multiplication coefficient	Input
x	For daxpby, x is of double-precision floating-point type. For saxpby, x is of single-precision floating-point type. For caxpby, x is of single-precision complex number type. For zaxpby, x is of double-precision complex number type.	Vector x. The vector size is at least (1+(n-1)*abs(incx)).	Input
incx	Integer	Increment for the elements of vector x	Input
beta	Double-precision floating-point type for daxpby Single-precision floating-point type for saxpby Single-precision complex number type for caxpby Double-precision complex number type for zaxpby	Multiplication coefficient	Input
y	For daxpby, y is of double-precision floating-point type. For saxpby, y is of single-precision floating-point type. For caxpby, y is of single-precision complex number type. For zaxpby, y is of double-precision complex number type.	Vector y. The vector size is at least (1+(n-1)*abs(incy)).	Input/Output
incy	Integer	Increment for the elements of vector y	Input

Dependencies

#include "kblas.h"

Examples

C interface:

    float alpha = 2.0; 
    float beta = 3.0;
    int n = 5, incx = 1, incy = 1; 
    /** 
     *    X:f 0.340188, -0.105617, 0.283099, 0.298440, 0.411647 
     *    Y: -0.302449, -0.164777, 0.268230, -0.222225, 0.053970 
     */ 
    float x[5] = {0.340188, -0.105617, 0.283099, 0.298440, 0.411647}; 
    float y[5] = {-0.302449, -0.164777, 0.268230, -0.222225, 0.053970}; 
 
    cblas_saxpby(n, alpha, x, incx, beta, y, incy); 
    /** 
     *    Output Y: -0.226971, -0.705565, 1.370888, -0.069795, 0.985204 
     */

Fortran interface:

      REAL(4) :: ALPHA=2.0 
      REAL(4) :: BETA=3.0 
      INTEGER :: N=5 
      INTEGER :: INCX=1 
      INTEGER :: INCY=1 
      REAL(4) :: X(5) 
      DATA X /0.340188, -0.105617, 0.283099, 0.298440, 0.411647/ 
      REAL(4) :: Y(5) 
      DATA Y /-0.302449, -0.164777, 0.268230, -0.222225, 0.053970/ 
      CALL SAXPBY(N, ALPHA, X, INCX, BETA, Y, INCY) 
 
*     Output Y : -0.226971, -0.705565, 1.370888, -0.069795, 0.985204

Parent topic: KML_BLAS-like Extensions