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?scal

Compute the product of a vector and a coefficient, that is, .

alpha is a multiplication coefficient, and x is a vector including n elements.

Interface Definition

C interface:

void cblas_dscal(const BLASINT N, const double alpha, double *X, const BLASINT incX);

void cblas_sscal(const BLASINT N, const float alpha, float *X, const BLASINT incX);

void cblas_cscal(const BLASINT N, const void *alpha, void *X, const BLASINT incX);

void cblas_zscal(const BLASINT N, const void *alpha, void *X, const BLASINT incX);

void cblas_csscal(const BLASINT N, const double alpha, void *X, const BLASINT incX);

void cblas_zdscal(const BLASINT N, const double alpha, void *X, const BLASINT incX);

Fortran interface:

CALL SSCAL(N, ALPAH, X, INCX)

CALL DSCAL(N, ALPAH, X, INCX)

CALL CSCAL(N, ALPAH, X, INCX)

CALL ZSCAL(N, ALPAH, X, INCX)

CALL CSSCAL(N, ALPAH, X, INCX)

CALL ZDSCAL(N, ALPAH, X, INCX)

Parameters

Parameter

Type

Description

Input/Output

N

Integer

Number of elements in vector X

Input

alpha
  • For dscal, alpha is of double-precision floating-point type.
  • For sscal, alpha is of single-precision floating-point type.
  • For cscal, alpha is of single-precision complex number type.
  • For zscal, alpha is of double-precision complex number type.
  • For csscal, alpha is of single-precision floating-point type.
  • For zdscal, alpha is of double-precision floating-point type.

Coefficient

Input

X
  • For dscal, X is of double-precision floating-point type.
  • For sscal, X is of single-precision floating-point type.
  • For cscal, X is of single-precision complex number type.
  • For zscal, X is of double-precision complex number type.
  • For csscal, X is of single-precision complex number type.
  • For zdscal, X is of double-precision complex number type.

Vector X. The vector size is at least (1+(n-1)*abs(incX)).

Input/Output

incX

Integer

Increment for the elements of vector X

Input

Dependencies

#include "kblas.h"

Examples

C interface:

    float alpha = 2.0; 
    int n = 5, incx = 1; 
    /** 
     * X: 0.340188, -0.105617, 0.283099, 0.298440, 0.411647 
     */ 
    float x[5] = {0.340188, -0.105617, 0.283099, 0.298440, 0.411647}; 
 
    cblas_sscal(n, alpha, x, incx); 
    /** 
     * Output X: 0.680375, -0.211234, 0.566198, 0.596880, 0.823295 
     */

Fortran interface:

      REAL(4) :: ALPHA=2.0 
      INTEGER :: N=5 
      INTEGER :: INCX=1 
      REAL(4) :: X(5) 
      DATA X /0.340188, -0.105617, 0.283099, 0.298440, 0.411647/ 
      EXTERNAL SSCAL 
      CALL SSCAL(N, ALPHA, X, INCX) 
 
*     Output X: 0.680375, -0.211234, 0.566198, 0.596880, 0.823295