?laswp

Perform a series of row exchange operations on a matrix.

Interface Definition

C interface:

void slaswp_(const int *n, float *a, const int *lda, const int *k1, const int *k2, const int *ipiv, const int *incx);

void dlaswp_(const int *n, double *a, const int *lda, const int *k1, const int *k2, const int *ipiv, const int *incx);

void claswp_(const int *n, float _Complex *a, const int *lda, const int *k1, const int *k2, const int *ipiv, const int *incx);

void zlaswp_(const int *n, double _Complex *a, const int *lda, const int *k1, const int *k2, const int *ipiv, const int *incx);

Fortran interface:

SLASWP(N, A, LDA, K1, K2, IPIV, INCX);

DLASWP(N, A, LDA, K1, K2, IPIV, INCX);

CLASWP(N, A, LDA, K1, K2, IPIV, INCX);

ZLASWP(N, A, LDA, K1, K2, IPIV, INCX);

Parameters

Parameter	Type	Description	Input/Output
N	Integer	Number of columns in matrix A.	Input
A	Single-precision floating-point type for slaswp Double-precision floating-point type for dlaswp Complex single-precision type for claswp Complex double-precision type for zlaswp	Matrix A with a size of LDA*N. Stores matrix A before this function is called. Stores the matrix after this function is called.	Input, output
LDA	Integer	Leading dimension of matrix A.	Input
K1	Integer	Index value of IPIV. It indicates the start row of the swap.	Input
K2	Integer	Index value of IPIV. It indicates the end row of the swap.	Input
IPIV	Integer array	Index array for the swap. The size is K1+(K2-K1)*abs(INCX).	Input
INCX	Integer	Step of the IPIV value.	Input

Dependency

#include "klapack.h"

Examples

C interface:

const int n = 4;
const int lda = n;
const int k1 = 1;
const int k2 = 2;
const int incx = 1;

double a[] = { 1.0, 1.0, 1.0, 1.0,
               2.0, 2.0, 2.0, 2.0,
               8.0, 3.0, 3.0, 3.0,
               4.0, 4.0, 4.0, 4.0};
int ipiv[3] = {3,1};
dlaswp_(&n, a, &lda, &k1, &k2, ipiv, &incx);
/* 
 * Output: 
 * a output:
 * 
 *  1.000000    1.000000    1.000000    1.000000
 *  2.000000    2.000000    2.000000    2.000000
 *  3.000000    3.000000    8.000000    3.000000
 *  4.000000    4.000000    4.000000    4.000000

Fortran interface:

PARAMETER (n = 4) 
PARAMETER (lda = n)
PARAMETER (k1 = 1) 
PARAMETER (k2 = 2)
PARAMETER (incx = 1)
REAL(8) :: a(lda, n)  
INTEGER :: ipiv(3)
  
DATA a / 1.0, 1.0, 1.0, 1.0,
$        2.0, 2.0, 2.0, 2.0,
$        8.0, 3.0, 3.0, 3.0,
$        4.0, 4.0, 4.0, 4.0 /
DATA ipiv / 3, 1 /
 EXTERNAL DLASWP
 CALL DLASWP(n, a, lda, k1, k2, ipiv, incx);
* 
* Output: 
* a output (stored in column-major)
*  1.000000    1.000000    1.000000    1.000000
*  2.000000    2.000000    2.000000    2.000000
*  3.000000    3.000000    8.000000    3.000000
*  4.000000    4.000000    4.000000    4.000000

Parent topic: Auxiliary Functions