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?swap

Exchange elements between two vectors.

Interface Definition

C interface:

void cblas_sswap(const BLASINT n, float *x, const BLASINT incx, float *y, const BLASINT incy);

void cblas_dswap(const BLASINT n, double *x, const BLASINT incx, double *y, const BLASINT incy);

void cblas_cswap(const BLASINT n, void *x, const BLASINT incx, void *y, const BLASINT incy);

void cblas_zswap(const BLASINT n, void *x, const BLASINT incx, void *y, const BLASINT incy);

Fortran interface:

CALL SSWAP(N, SX, INCX, SY, INCY)

CALL DSWAP(N, SX, INCX, SY, INCY)

CALL CSWAP(N, SX, INCX, SY, INCY)

CALL ZSWAP(N, SX, INCX, SY, INCY)

Parameters

Parameter

Type

Description

Input/Output

n

Integer

Number of elements in the x and y vectors

Input

x
  • For sswap, x is of double-precision floating-point type.
  • For dswap, x is of single-precision floating-point type.
  • For cswap, x is of single-precision complex number type.
  • For zswap, 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

y
  • For sswap, y is of double-precision floating-point type.
  • For dswap, y is of single-precision floating-point type.
  • For cswap, y is of single-precision complex number type.
  • For zswap, 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

Vector unit increment step in y

Input

Dependencies

#include "kblas.h"

Examples

C interface:

    int n = 5, incx = 1, incy = 1; 
    /* 
     *  Input X:  0.340188, -0.105617, 0.283099, 0.298440, 0.411647 
     *  Input 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_sswap(n, x, incx, y, incy); 
    /* 
     *  Output X: -0.302449, -0.164777, 0.268230, -0.222225, 0.053970 
     *  Output Y: 0.340188, -0.105617, 0.283099, 0.298440, 0.411647 
     * */

Fortran interface:

      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/ 
      EXTERNAL SSWAP 
      CALL SSWAP(N, X, INCX, Y, INCY) 
 
*     Output X: -0.302449, -0.164777, 0.268230, -0.222225, 0.053970 
*     Output Y: 0.340188, -0.105617, 0.283099, 0.298440, 0.411647