# dlaset (l) - Linux Man Pages

## NAME

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

## SYNOPSIS

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

CHARACTER UPLO

INTEGER LDA, M, N

DOUBLE PRECISION ALPHA, BETA

DOUBLE PRECISION A( LDA, * )

## PURPOSE

DLASET 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. = aqUaq: Upper triangular part is set; the strictly lower triangular part of A is not changed. = aqLaq: 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) DOUBLE PRECISION
The constant to which the offdiagonal elements are to be set.
BETA (input) DOUBLE PRECISION
The constant to which the diagonal elements are to be set.
A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On exit, the leading m-by-n submatrix of A is set as follows: if UPLO = aqUaq, A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n, if UPLO = aqLaq, 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).