 LAPACK 3.11.0 LAPACK: Linear Algebra PACKage
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## ◆ slaset()

 subroutine slaset ( character UPLO, integer M, integer N, real ALPHA, real BETA, real, dimension( lda, * ) A, integer LDA )

SLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.

Purpose:
``` SLASET initializes an m-by-n matrix A to BETA on the diagonal and
ALPHA on the offdiagonals.```
Parameters
 [in] UPLO ``` UPLO is 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.``` [in] M ``` M is INTEGER The number of rows of the matrix A. M >= 0.``` [in] N ``` N is INTEGER The number of columns of the matrix A. N >= 0.``` [in] ALPHA ``` ALPHA is REAL The constant to which the offdiagonal elements are to be set.``` [in] BETA ``` BETA is REAL The constant to which the diagonal elements are to be set.``` [out] A ``` A is 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).``` [in] LDA ``` LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M).```

Definition at line 109 of file slaset.f.

110*
111* -- LAPACK auxiliary routine --
112* -- LAPACK is a software package provided by Univ. of Tennessee, --
113* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
114*
115* .. Scalar Arguments ..
116 CHARACTER UPLO
117 INTEGER LDA, M, N
118 REAL ALPHA, BETA
119* ..
120* .. Array Arguments ..
121 REAL A( LDA, * )
122* ..
123*
124* =====================================================================
125*
126* .. Local Scalars ..
127 INTEGER I, J
128* ..
129* .. External Functions ..
130 LOGICAL LSAME
131 EXTERNAL lsame
132* ..
133* .. Intrinsic Functions ..
134 INTRINSIC min
135* ..
136* .. Executable Statements ..
137*
138 IF( lsame( uplo, 'U' ) ) THEN
139*
140* Set the strictly upper triangular or trapezoidal part of the
141* array to ALPHA.
142*
143 DO 20 j = 2, n
144 DO 10 i = 1, min( j-1, m )
145 a( i, j ) = alpha
146 10 CONTINUE
147 20 CONTINUE
148*
149 ELSE IF( lsame( uplo, 'L' ) ) THEN
150*
151* Set the strictly lower triangular or trapezoidal part of the
152* array to ALPHA.
153*
154 DO 40 j = 1, min( m, n )
155 DO 30 i = j + 1, m
156 a( i, j ) = alpha
157 30 CONTINUE
158 40 CONTINUE
159*
160 ELSE
161*
162* Set the leading m-by-n submatrix to ALPHA.
163*
164 DO 60 j = 1, n
165 DO 50 i = 1, m
166 a( i, j ) = alpha
167 50 CONTINUE
168 60 CONTINUE
169 END IF
170*
171* Set the first min(M,N) diagonal elements to BETA.
172*
173 DO 70 i = 1, min( m, n )
174 a( i, i ) = beta
175 70 CONTINUE
176*
177 RETURN
178*
179* End of SLASET
180*
logical function lsame(CA, CB)
LSAME
Definition: lsame.f:53