NAME

DLASET - initialize 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. = ’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) 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 = ’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).

  —  LAPACK version 2.0  —  08 October 1994