LAPACK  3.4.2 LAPACK: Linear Algebra PACKage
claset.f
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1 *> \brief \b CLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.
2 *
3 * =========== DOCUMENTATION ===========
4 *
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17 *
18 * Definition:
19 * ===========
20 *
21 * SUBROUTINE CLASET( UPLO, M, N, ALPHA, BETA, A, LDA )
22 *
23 * .. Scalar Arguments ..
24 * CHARACTER UPLO
25 * INTEGER LDA, M, N
26 * COMPLEX ALPHA, BETA
27 * ..
28 * .. Array Arguments ..
29 * COMPLEX A( LDA, * )
30 * ..
31 *
32 *
33 *> \par Purpose:
34 * =============
35 *>
36 *> \verbatim
37 *>
38 *> CLASET initializes a 2-D array A to BETA on the diagonal and
39 *> ALPHA on the offdiagonals.
40 *> \endverbatim
41 *
42 * Arguments:
43 * ==========
44 *
45 *> \param[in] UPLO
46 *> \verbatim
47 *> UPLO is CHARACTER*1
48 *> Specifies the part of the matrix A to be set.
49 *> = 'U': Upper triangular part is set. The lower triangle
50 *> is unchanged.
51 *> = 'L': Lower triangular part is set. The upper triangle
52 *> is unchanged.
53 *> Otherwise: All of the matrix A is set.
54 *> \endverbatim
55 *>
56 *> \param[in] M
57 *> \verbatim
58 *> M is INTEGER
59 *> On entry, M specifies the number of rows of A.
60 *> \endverbatim
61 *>
62 *> \param[in] N
63 *> \verbatim
64 *> N is INTEGER
65 *> On entry, N specifies the number of columns of A.
66 *> \endverbatim
67 *>
68 *> \param[in] ALPHA
69 *> \verbatim
70 *> ALPHA is COMPLEX
71 *> All the offdiagonal array elements are set to ALPHA.
72 *> \endverbatim
73 *>
74 *> \param[in] BETA
75 *> \verbatim
76 *> BETA is COMPLEX
77 *> All the diagonal array elements are set to BETA.
78 *> \endverbatim
79 *>
80 *> \param[in,out] A
81 *> \verbatim
82 *> A is COMPLEX array, dimension (LDA,N)
83 *> On entry, the m by n matrix A.
84 *> On exit, A(i,j) = ALPHA, 1 <= i <= m, 1 <= j <= n, i.ne.j;
85 *> A(i,i) = BETA , 1 <= i <= min(m,n)
86 *> \endverbatim
87 *>
88 *> \param[in] LDA
89 *> \verbatim
90 *> LDA is INTEGER
91 *> The leading dimension of the array A. LDA >= max(1,M).
92 *> \endverbatim
93 *
94 * Authors:
95 * ========
96 *
97 *> \author Univ. of Tennessee
98 *> \author Univ. of California Berkeley
99 *> \author Univ. of Colorado Denver
100 *> \author NAG Ltd.
101 *
102 *> \date September 2012
103 *
104 *> \ingroup complexOTHERauxiliary
105 *
106 * =====================================================================
107  SUBROUTINE claset( UPLO, M, N, ALPHA, BETA, A, LDA )
108 *
109 * -- LAPACK auxiliary routine (version 3.4.2) --
110 * -- LAPACK is a software package provided by Univ. of Tennessee, --
111 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
112 * September 2012
113 *
114 * .. Scalar Arguments ..
115  CHARACTER uplo
116  INTEGER lda, m, n
117  COMPLEX alpha, beta
118 * ..
119 * .. Array Arguments ..
120  COMPLEX a( lda, * )
121 * ..
122 *
123 * =====================================================================
124 *
125 * .. Local Scalars ..
126  INTEGER i, j
127 * ..
128 * .. External Functions ..
129  LOGICAL lsame
130  EXTERNAL lsame
131 * ..
132 * .. Intrinsic Functions ..
133  INTRINSIC min
134 * ..
135 * .. Executable Statements ..
136 *
137  IF( lsame( uplo, 'U' ) ) THEN
138 *
139 * Set the diagonal to BETA and the strictly upper triangular
140 * part of the array to ALPHA.
141 *
142  DO 20 j = 2, n
143  DO 10 i = 1, min( j-1, m )
144  a( i, j ) = alpha
145  10 continue
146  20 continue
147  DO 30 i = 1, min( n, m )
148  a( i, i ) = beta
149  30 continue
150 *
151  ELSE IF( lsame( uplo, 'L' ) ) THEN
152 *
153 * Set the diagonal to BETA and the strictly lower triangular
154 * part of the array to ALPHA.
155 *
156  DO 50 j = 1, min( m, n )
157  DO 40 i = j + 1, m
158  a( i, j ) = alpha
159  40 continue
160  50 continue
161  DO 60 i = 1, min( n, m )
162  a( i, i ) = beta
163  60 continue
164 *
165  ELSE
166 *
167 * Set the array to BETA on the diagonal and ALPHA on the
168 * offdiagonal.
169 *
170  DO 80 j = 1, n
171  DO 70 i = 1, m
172  a( i, j ) = alpha
173  70 continue
174  80 continue
175  DO 90 i = 1, min( m, n )
176  a( i, i ) = beta
177  90 continue
178  END IF
179 *
180  return
181 *
182 * End of CLASET
183 *
184  END