|
2329
|
1 SUBROUTINE DLASET( UPLO, M, N, ALPHA, BETA, A, LDA ) |
|
|
2 * |
|
3333
|
3 * -- LAPACK auxiliary routine (version 3.0) -- |
|
2329
|
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 |
