1*> \brief \b DLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.
2*
3*  =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6*            http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
9*> Download DLASET + dependencies
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaset.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaset.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaset.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18*  Definition:
19*  ===========
20*
21*       SUBROUTINE DLASET( UPLO, M, N, ALPHA, BETA, A, LDA )
22*
23*       .. Scalar Arguments ..
24*       CHARACTER          UPLO
25*       INTEGER            LDA, M, N
26*       DOUBLE PRECISION   ALPHA, BETA
27*       ..
28*       .. Array Arguments ..
29*       DOUBLE PRECISION   A( LDA, * )
30*       ..
31*
32*
33*> \par Purpose:
34*  =============
35*>
36*> \verbatim
37*>
38*> DLASET initializes an m-by-n matrix 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 strictly lower
50*>                      triangular part of A is not changed.
51*>          = 'L':      Lower triangular part is set; the strictly upper
52*>                      triangular part of A is not changed.
53*>          Otherwise:  All of the matrix A is set.
54*> \endverbatim
55*>
56*> \param[in] M
57*> \verbatim
58*>          M is INTEGER
59*>          The number of rows of the matrix A.  M >= 0.
60*> \endverbatim
61*>
62*> \param[in] N
63*> \verbatim
64*>          N is INTEGER
65*>          The number of columns of the matrix A.  N >= 0.
66*> \endverbatim
67*>
68*> \param[in] ALPHA
69*> \verbatim
70*>          ALPHA is DOUBLE PRECISION
71*>          The constant to which the offdiagonal elements are to be set.
72*> \endverbatim
73*>
74*> \param[in] BETA
75*> \verbatim
76*>          BETA is DOUBLE PRECISION
77*>          The constant to which the diagonal elements are to be set.
78*> \endverbatim
79*>
80*> \param[out] A
81*> \verbatim
82*>          A is DOUBLE PRECISION array, dimension (LDA,N)
83*>          On exit, the leading m-by-n submatrix of A is set as follows:
84*>
85*>          if UPLO = 'U', A(i,j) = ALPHA, 1<=i<=j-1, 1<=j<=n,
86*>          if UPLO = 'L', A(i,j) = ALPHA, j+1<=i<=m, 1<=j<=n,
87*>          otherwise,     A(i,j) = ALPHA, 1<=i<=m, 1<=j<=n, i.ne.j,
88*>
89*>          and, for all UPLO, A(i,i) = BETA, 1<=i<=min(m,n).
90*> \endverbatim
91*>
92*> \param[in] LDA
93*> \verbatim
94*>          LDA is INTEGER
95*>          The leading dimension of the array A.  LDA >= max(1,M).
96*> \endverbatim
97*
98*  Authors:
99*  ========
100*
101*> \author Univ. of Tennessee
102*> \author Univ. of California Berkeley
103*> \author Univ. of Colorado Denver
104*> \author NAG Ltd.
105*
106*> \date December 2016
107*
108*> \ingroup OTHERauxiliary
109*
110*  =====================================================================
111      SUBROUTINE DLASET( UPLO, M, N, ALPHA, BETA, A, LDA )
112*
113*  -- LAPACK auxiliary routine (version 3.7.0) --
114*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
115*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
116*     December 2016
117*
118*     .. Scalar Arguments ..
119      CHARACTER          UPLO
120      INTEGER            LDA, M, N
121      DOUBLE PRECISION   ALPHA, BETA
122*     ..
123*     .. Array Arguments ..
124      DOUBLE PRECISION   A( LDA, * )
125*     ..
126*
127* =====================================================================
128*
129*     .. Local Scalars ..
130      INTEGER            I, J
131*     ..
132*     .. External Functions ..
133      LOGICAL            LSAME
134      EXTERNAL           LSAME
135*     ..
136*     .. Intrinsic Functions ..
137      INTRINSIC          MIN
138*     ..
139*     .. Executable Statements ..
140*
141      IF( LSAME( UPLO, 'U' ) ) THEN
142*
143*        Set the strictly upper triangular or trapezoidal part of the
144*        array to ALPHA.
145*
146         DO 20 J = 2, N
147            DO 10 I = 1, MIN( J-1, M )
148               A( I, J ) = ALPHA
149   10       CONTINUE
150   20    CONTINUE
151*
152      ELSE IF( LSAME( UPLO, 'L' ) ) THEN
153*
154*        Set the strictly lower triangular or trapezoidal part of the
155*        array to ALPHA.
156*
157         DO 40 J = 1, MIN( M, N )
158            DO 30 I = J + 1, M
159               A( I, J ) = ALPHA
160   30       CONTINUE
161   40    CONTINUE
162*
163      ELSE
164*
165*        Set the leading m-by-n submatrix to ALPHA.
166*
167         DO 60 J = 1, N
168            DO 50 I = 1, M
169               A( I, J ) = ALPHA
170   50       CONTINUE
171   60    CONTINUE
172      END IF
173*
174*     Set the first min(M,N) diagonal elements to BETA.
175*
176      DO 70 I = 1, MIN( M, N )
177         A( I, I ) = BETA
178   70 CONTINUE
179*
180      RETURN
181*
182*     End of DLASET
183*
184      END
185