?laset

Initialize an m*n matrix and set the diagonal elements to beta and the non-diagonal elements to alpha.

Interface Definition

C interface:

void slaset_(const char *uplo, const int *m, const int *n, const float *alpha, const float *beta, float *a, const int *lda);

void dlaset_(const char *uplo, const int *m, const int *n, const double *alpha, const double *beta, double *a, const int *lda);

void claset_(const char *uplo, const int *m, const int *n, const float _Complex *alpha, const float _Complex *beta, float _Complex *a, const int *lda);

void zlaset_(const char *uplo, const int *m, const int *n, const double _Complex *alpha, const double _Complex *beta, double _Complex *a, const int *lda);

Fortran interface:

SLASET(UPLO, M, N, ALPHA, BETA, A, LDA);

DLASET(UPLO, M, N, ALPHA, BETA, A, LDA);

CLASET(UPLO, M, N, ALPHA, BETA, A, LDA);

ZLASET(UPLO, M, N, ALPHA, BETA, A, LDA);

Parameters

Parameter	Type	Description	Input/Output
UPLO	Character	'U': initializes the upper triangular part of matrix A. 'L': initializes the lower triangular part of matrix A. Others: initializes the entire matrix A.	Input
M	Integer	Number of rows in matrix A.	Input
N	Integer	Number of columns in matrix A.	Input
ALPHA	Single-precision floating-point type for slaset Double-precision floating-point type for dlaset Complex single-precision type for claset Complex double-precision type for zlaset	Non-diagonal element value in matrix A.	Input
BETA	Single-precision floating-point type for slaset Double-precision floating-point type for dlaset Complex single-precision type for claset Complex double-precision type for zlaset	Diagonal element value of matrix A.	Input
A	A single-precision floating-point array for slaset A double-precision floating-point array for dlaset A complex single-precision array for claset A complex double-precision array for zlaset	Matrix A, with a dimension of (LDA, N).	Output
LDA	Integer	Leading dimension of matrix A.	Input

Dependency

#include "klapack.h"

Examples

C interface:

const char uplo = 'U';
const int m = 4;
const int n = 4;
const int lda = m;

const double alpha = 2.0;
const double beta = 1.0;
double *a = (double*)malloc(lda * n * sizeof(double));
for (int i = 0; i < lda * n; i++) {
    a[i] = -1;
}

dlaset_(&uplo, &m, &n, &alpha, &beta, a, &lda);
/* 
 * Output: 
 * a output (stored in column-major)
 *   
 *  1.000000        2.000000        2.000000        2.000000
 *  -1.000000       1.000000        2.000000        2.000000
 *  -1.000000       -1.000000       1.000000        2.000000
 *  -1.000000       -1.000000       -1.000000       1.000000

Fortran interface:

CHARACTER :: uplo = "U"
PARAMETER (m = 4) 
PARAMETER (n = 4)
PARAMETER (lda = 4) 
REAL(8) :: alpha 
REAL(8) :: beta
REAL(8) :: a(lda, n)  
  
DATA alpha / 2.0 / 
DATA beta / 1.0 /
DATA a / -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 /
 EXTERNAL DLASET
 CALL DLASET(uplo, m, n, alpha, beta, a, lda);
* 
* Output: 
* a output (stored in column-major)
*  1.000000        2.000000        2.000000        2.000000
*  -1.000000       1.000000        2.000000        2.000000
*  -1.000000       -1.000000       1.000000        2.000000
*  -1.000000       -1.000000       -1.000000       1.000000

Parent topic: Auxiliary Functions