KTH framework for Nek5000 toolboxes; testing version  0.0.1
dlaset.f
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1  SUBROUTINE dlaset( UPLO, M, N, ALPHA, BETA, A, LDA )
2 *
3 * -- LAPACK auxiliary routine (version 3.0) --
4 * Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
5 * Courant Institute, Argonne National Lab, and Rice University
6 * October 31, 1992
7 *
8 * .. Scalar Arguments ..
9  CHARACTER UPLO
10  INTEGER LDA, M, N
11  DOUBLE PRECISION ALPHA, BETA
12 * ..
13 * .. Array Arguments ..
14  DOUBLE PRECISION A( LDA, * )
15 * ..
16 *
17 * Purpose
18 * =======
19 *
20 * DLASET initializes an m-by-n matrix A to BETA on the diagonal and
21 * ALPHA on the offdiagonals.
22 *
23 * Arguments
24 * =========
25 *
26 * UPLO (input) CHARACTER*1
27 * Specifies the part of the matrix A to be set.
28 * = 'U': Upper triangular part is set; the strictly lower
29 * triangular part of A is not changed.
30 * = 'L': Lower triangular part is set; the strictly upper
31 * triangular part of A is not changed.
32 * Otherwise: All of the matrix A is set.
33 *
34 * M (input) INTEGER
35 * The number of rows of the matrix A. M >= 0.
36 *
37 * N (input) INTEGER
38 * The number of columns of the matrix A. N >= 0.
39 *
40 * ALPHA (input) DOUBLE PRECISION
41 * The constant to which the offdiagonal elements are to be set.
42 *
43 * BETA (input) DOUBLE PRECISION
44 * The constant to which the diagonal elements are to be set.
45 *
46 * A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
47 * On exit, the leading m-by-n submatrix of A is set as follows:
48 *
49 * if UPLO = 'U', A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n,
50 * if UPLO = 'L', A(i,j) = ALPHA, j+1<=i<=m, 1<=j<=n,
51 * otherwise, A(i,j) = ALPHA, 1<=i<=m, 1<=j<=n, i.ne.j,
52 *
53 * and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n).
54 *
55 * LDA (input) INTEGER
56 * The leading dimension of the array A. LDA >= max(1,M).
57 *
58 * =====================================================================
59 *
60 * .. Local Scalars ..
61  INTEGER I, J
62 * ..
63 * .. External Functions ..
64  LOGICAL LSAME
65  EXTERNAL lsame
66 * ..
67 * .. Intrinsic Functions ..
68  INTRINSIC min
69 * ..
70 * .. Executable Statements ..
71 *
72  IF( lsame( uplo, 'U' ) ) THEN
73 *
74 * Set the strictly upper triangular or trapezoidal part of the
75 * array to ALPHA.
76 *
77  DO 20 j = 2, n
78  DO 10 i = 1, min( j-1, m )
79  a( i, j ) = alpha
80  10 CONTINUE
81  20 CONTINUE
82 *
83  ELSE IF( lsame( uplo, 'L' ) ) THEN
84 *
85 * Set the strictly lower triangular or trapezoidal part of the
86 * array to ALPHA.
87 *
88  DO 40 j = 1, min( m, n )
89  DO 30 i = j + 1, m
90  a( i, j ) = alpha
91  30 CONTINUE
92  40 CONTINUE
93 *
94  ELSE
95 *
96 * Set the leading m-by-n submatrix to ALPHA.
97 *
98  DO 60 j = 1, n
99  DO 50 i = 1, m
100  a( i, j ) = alpha
101  50 CONTINUE
102  60 CONTINUE
103  END IF
104 *
105 * Set the first min(M,N) diagonal elements to BETA.
106 *
107  DO 70 i = 1, min( m, n )
108  a( i, i ) = beta
109  70 CONTINUE
110 *
111  RETURN
112 *
113 * End of DLASET
114 *
115  END
subroutine dlaset(UPLO, M, N, ALPHA, BETA, A, LDA)
Definition: dlaset.f:2