aboutsummaryrefslogtreecommitdiff
path: root/SRC/zlacrm.f
blob: a3f919d0e1ea5d4f4913436a46165eb29c3374b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
*> \brief \b ZLACRM multiplies a complex matrix by a square real matrix.
*
*  =========== DOCUMENTATION ===========
*
* Online html documentation available at
*            http://www.netlib.org/lapack/explore-html/
*
*> \htmlonly
*> Download ZLACRM + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlacrm.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlacrm.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlacrm.f">
*> [TXT]</a>
*> \endhtmlonly
*
*  Definition:
*  ===========
*
*       SUBROUTINE ZLACRM( M, N, A, LDA, B, LDB, C, LDC, RWORK )
*
*       .. Scalar Arguments ..
*       INTEGER            LDA, LDB, LDC, M, N
*       ..
*       .. Array Arguments ..
*       DOUBLE PRECISION   B( LDB, * ), RWORK( * )
*       COMPLEX*16         A( LDA, * ), C( LDC, * )
*       ..
*
*
*> \par Purpose:
*  =============
*>
*> \verbatim
*>
*> ZLACRM performs a very simple matrix-matrix multiplication:
*>          C := A * B,
*> where A is M by N and complex; B is N by N and real;
*> C is M by N and complex.
*> \endverbatim
*
*  Arguments:
*  ==========
*
*> \param[in] M
*> \verbatim
*>          M is INTEGER
*>          The number of rows of the matrix A and of the matrix C.
*>          M >= 0.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*>          N is INTEGER
*>          The number of columns and rows of the matrix B and
*>          the number of columns of the matrix C.
*>          N >= 0.
*> \endverbatim
*>
*> \param[in] A
*> \verbatim
*>          A is COMPLEX*16 array, dimension (LDA, N)
*>          On entry, A contains the M by N matrix A.
*> \endverbatim
*>
*> \param[in] LDA
*> \verbatim
*>          LDA is INTEGER
*>          The leading dimension of the array A. LDA >=max(1,M).
*> \endverbatim
*>
*> \param[in] B
*> \verbatim
*>          B is DOUBLE PRECISION array, dimension (LDB, N)
*>          On entry, B contains the N by N matrix B.
*> \endverbatim
*>
*> \param[in] LDB
*> \verbatim
*>          LDB is INTEGER
*>          The leading dimension of the array B. LDB >=max(1,N).
*> \endverbatim
*>
*> \param[out] C
*> \verbatim
*>          C is COMPLEX*16 array, dimension (LDC, N)
*>          On exit, C contains the M by N matrix C.
*> \endverbatim
*>
*> \param[in] LDC
*> \verbatim
*>          LDC is INTEGER
*>          The leading dimension of the array C. LDC >=max(1,N).
*> \endverbatim
*>
*> \param[out] RWORK
*> \verbatim
*>          RWORK is DOUBLE PRECISION array, dimension (2*M*N)
*> \endverbatim
*
*  Authors:
*  ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date December 2016
*
*> \ingroup complex16OTHERauxiliary
*
*  =====================================================================
      SUBROUTINE ZLACRM( M, N, A, LDA, B, LDB, C, LDC, RWORK )
*
*  -- LAPACK auxiliary routine (version 3.7.0) --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*     December 2016
*
*     .. Scalar Arguments ..
      INTEGER            LDA, LDB, LDC, M, N
*     ..
*     .. Array Arguments ..
      DOUBLE PRECISION   B( LDB, * ), RWORK( * )
      COMPLEX*16         A( LDA, * ), C( LDC, * )
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
      DOUBLE PRECISION   ONE, ZERO
      PARAMETER          ( ONE = 1.0D0, ZERO = 0.0D0 )
*     ..
*     .. Local Scalars ..
      INTEGER            I, J, L
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          DBLE, DCMPLX, DIMAG
*     ..
*     .. External Subroutines ..
      EXTERNAL           DGEMM
*     ..
*     .. Executable Statements ..
*
*     Quick return if possible.
*
      IF( ( M.EQ.0 ) .OR. ( N.EQ.0 ) )
     $   RETURN
*
      DO 20 J = 1, N
         DO 10 I = 1, M
            RWORK( ( J-1 )*M+I ) = DBLE( A( I, J ) )
   10    CONTINUE
   20 CONTINUE
*
      L = M*N + 1
      CALL DGEMM( 'N', 'N', M, N, N, ONE, RWORK, M, B, LDB, ZERO,
     $            RWORK( L ), M )
      DO 40 J = 1, N
         DO 30 I = 1, M
            C( I, J ) = RWORK( L+( J-1 )*M+I-1 )
   30    CONTINUE
   40 CONTINUE
*
      DO 60 J = 1, N
         DO 50 I = 1, M
            RWORK( ( J-1 )*M+I ) = DIMAG( A( I, J ) )
   50    CONTINUE
   60 CONTINUE
      CALL DGEMM( 'N', 'N', M, N, N, ONE, RWORK, M, B, LDB, ZERO,
     $            RWORK( L ), M )
      DO 80 J = 1, N
         DO 70 I = 1, M
            C( I, J ) = DCMPLX( DBLE( C( I, J ) ),
     $                  RWORK( L+( J-1 )*M+I-1 ) )
   70    CONTINUE
   80 CONTINUE
*
      RETURN
*
*     End of ZLACRM
*
      END