LAPACK  3.6.1 LAPACK: Linear Algebra PACKage
zlag2c.f
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1 *> \brief \b ZLAG2C converts a complex double precision matrix to a complex single precision matrix.
2 *
3 * =========== DOCUMENTATION ===========
4 *
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17 *
18 * Definition:
19 * ===========
20 *
21 * SUBROUTINE ZLAG2C( M, N, A, LDA, SA, LDSA, INFO )
22 *
23 * .. Scalar Arguments ..
24 * INTEGER INFO, LDA, LDSA, M, N
25 * ..
26 * .. Array Arguments ..
27 * COMPLEX SA( LDSA, * )
28 * COMPLEX*16 A( LDA, * )
29 * ..
30 *
31 *
32 *> \par Purpose:
33 * =============
34 *>
35 *> \verbatim
36 *>
37 *> ZLAG2C converts a COMPLEX*16 matrix, SA, to a COMPLEX matrix, A.
38 *>
39 *> RMAX is the overflow for the SINGLE PRECISION arithmetic
40 *> ZLAG2C checks that all the entries of A are between -RMAX and
41 *> RMAX. If not the convertion is aborted and a flag is raised.
42 *>
43 *> This is an auxiliary routine so there is no argument checking.
44 *> \endverbatim
45 *
46 * Arguments:
47 * ==========
48 *
49 *> \param[in] M
50 *> \verbatim
51 *> M is INTEGER
52 *> The number of lines of the matrix A. M >= 0.
53 *> \endverbatim
54 *>
55 *> \param[in] N
56 *> \verbatim
57 *> N is INTEGER
58 *> The number of columns of the matrix A. N >= 0.
59 *> \endverbatim
60 *>
61 *> \param[in] A
62 *> \verbatim
63 *> A is COMPLEX*16 array, dimension (LDA,N)
64 *> On entry, the M-by-N coefficient matrix A.
65 *> \endverbatim
66 *>
67 *> \param[in] LDA
68 *> \verbatim
69 *> LDA is INTEGER
70 *> The leading dimension of the array A. LDA >= max(1,M).
71 *> \endverbatim
72 *>
73 *> \param[out] SA
74 *> \verbatim
75 *> SA is COMPLEX array, dimension (LDSA,N)
76 *> On exit, if INFO=0, the M-by-N coefficient matrix SA; if
77 *> INFO>0, the content of SA is unspecified.
78 *> \endverbatim
79 *>
80 *> \param[in] LDSA
81 *> \verbatim
82 *> LDSA is INTEGER
83 *> The leading dimension of the array SA. LDSA >= max(1,M).
84 *> \endverbatim
85 *>
86 *> \param[out] INFO
87 *> \verbatim
88 *> INFO is INTEGER
89 *> = 0: successful exit.
90 *> = 1: an entry of the matrix A is greater than the SINGLE
91 *> PRECISION overflow threshold, in this case, the content
92 *> of SA in exit is unspecified.
93 *> \endverbatim
94 *
95 * Authors:
96 * ========
97 *
98 *> \author Univ. of Tennessee
99 *> \author Univ. of California Berkeley
100 *> \author Univ. of Colorado Denver
101 *> \author NAG Ltd.
102 *
103 *> \date September 2012
104 *
105 *> \ingroup complex16OTHERauxiliary
106 *
107 * =====================================================================
108  SUBROUTINE zlag2c( M, N, A, LDA, SA, LDSA, INFO )
109 *
110 * -- LAPACK auxiliary routine (version 3.4.2) --
111 * -- LAPACK is a software package provided by Univ. of Tennessee, --
112 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
113 * September 2012
114 *
115 * .. Scalar Arguments ..
116  INTEGER INFO, LDA, LDSA, M, N
117 * ..
118 * .. Array Arguments ..
119  COMPLEX SA( ldsa, * )
120  COMPLEX*16 A( lda, * )
121 * ..
122 *
123 * =====================================================================
124 *
125 * .. Local Scalars ..
126  INTEGER I, J
127  DOUBLE PRECISION RMAX
128 * ..
129 * .. Intrinsic Functions ..
130  INTRINSIC dble, dimag
131 * ..
132 * .. External Functions ..
133  REAL SLAMCH
134  EXTERNAL slamch
135 * ..
136 * .. Executable Statements ..
137 *
138  rmax = slamch( 'O' )
139  DO 20 j = 1, n
140  DO 10 i = 1, m
141  IF( ( dble( a( i, j ) ).LT.-rmax ) .OR.
142  \$ ( dble( a( i, j ) ).GT.rmax ) .OR.
143  \$ ( dimag( a( i, j ) ).LT.-rmax ) .OR.
144  \$ ( dimag( a( i, j ) ).GT.rmax ) ) THEN
145  info = 1
146  GO TO 30
147  END IF
148  sa( i, j ) = a( i, j )
149  10 CONTINUE
150  20 CONTINUE
151  info = 0
152  30 CONTINUE
153  RETURN
154 *
155 * End of ZLAG2C
156 *
157  END
subroutine zlag2c(M, N, A, LDA, SA, LDSA, INFO)
ZLAG2C converts a complex double precision matrix to a complex single precision matrix.
Definition: zlag2c.f:109