man slaset (Fonctions bibliothèques) - initialize an m-by-n matrix A to BETA on the diagonal and ALPHA on the offdiagonals

NAME

SLASET - initialize an m-by-n matrix A to BETA on the diagonal and ALPHA on the offdiagonals

SYNOPSIS

SUBROUTINE SLASET(
UPLO, M, N, ALPHA, BETA, A, LDA )
CHARACTER UPLO
INTEGER LDA, M, N
REAL ALPHA, BETA
REAL A( LDA, * )

PURPOSE

SLASET initializes an m-by-n matrix A to BETA on the diagonal and ALPHA on the offdiagonals.

ARGUMENTS

UPLO (input) CHARACTER*1
Specifies the part of the matrix A to be set. = 'U': Upper triangular part is set; the strictly lower triangular part of A is not changed. = 'L': Lower triangular part is set; the strictly upper triangular part of A is not changed. Otherwise: All of the matrix A is set.
M (input) INTEGER
The number of rows of the matrix A. M >= 0.
N (input) INTEGER
The number of columns of the matrix A. N >= 0.
ALPHA (input) REAL
The constant to which the offdiagonal elements are to be set.
BETA (input) REAL
The constant to which the diagonal elements are to be set.
A (input/output) REAL array, dimension (LDA,N)
On exit, the leading m-by-n submatrix of A is set as follows:

if UPLO = 'U', A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n, if UPLO = 'L', A(i,j) = ALPHA, j+1<=i<=m, 1<=j<=n, otherwise, A(i,j) = ALPHA, 1<=i<=m, 1<=j<=n, i.ne.j,

and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n).

LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,M).