Annotation of rpl/lapack/lapack/dlat2s.f, revision 1.16
1.9 bertrand 1: *> \brief \b DLAT2S converts a double-precision triangular matrix to a single-precision triangular matrix.
1.7 bertrand 2: *
3: * =========== DOCUMENTATION ===========
4: *
1.13 bertrand 5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
1.7 bertrand 7: *
8: *> \htmlonly
1.13 bertrand 9: *> Download DLAT2S + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlat2s.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlat2s.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlat2s.f">
1.7 bertrand 15: *> [TXT]</a>
1.13 bertrand 16: *> \endhtmlonly
1.7 bertrand 17: *
18: * Definition:
19: * ===========
20: *
21: * SUBROUTINE DLAT2S( UPLO, N, A, LDA, SA, LDSA, INFO )
1.13 bertrand 22: *
1.7 bertrand 23: * .. Scalar Arguments ..
24: * CHARACTER UPLO
25: * INTEGER INFO, LDA, LDSA, N
26: * ..
27: * .. Array Arguments ..
28: * REAL SA( LDSA, * )
29: * DOUBLE PRECISION A( LDA, * )
30: * ..
1.13 bertrand 31: *
1.7 bertrand 32: *
33: *> \par Purpose:
34: * =============
35: *>
36: *> \verbatim
37: *>
38: *> DLAT2S converts a DOUBLE PRECISION triangular matrix, SA, to a SINGLE
39: *> PRECISION triangular matrix, A.
40: *>
41: *> RMAX is the overflow for the SINGLE PRECISION arithmetic
42: *> DLAS2S checks that all the entries of A are between -RMAX and
1.13 bertrand 43: *> RMAX. If not the conversion is aborted and a flag is raised.
1.7 bertrand 44: *>
45: *> This is an auxiliary routine so there is no argument checking.
46: *> \endverbatim
47: *
48: * Arguments:
49: * ==========
50: *
51: *> \param[in] UPLO
52: *> \verbatim
53: *> UPLO is CHARACTER*1
54: *> = 'U': A is upper triangular;
55: *> = 'L': A is lower triangular.
56: *> \endverbatim
57: *>
58: *> \param[in] N
59: *> \verbatim
60: *> N is INTEGER
61: *> The number of rows and columns of the matrix A. N >= 0.
62: *> \endverbatim
63: *>
64: *> \param[in] A
65: *> \verbatim
66: *> A is DOUBLE PRECISION array, dimension (LDA,N)
67: *> On entry, the N-by-N triangular coefficient matrix A.
68: *> \endverbatim
69: *>
70: *> \param[in] LDA
71: *> \verbatim
72: *> LDA is INTEGER
73: *> The leading dimension of the array A. LDA >= max(1,N).
74: *> \endverbatim
75: *>
76: *> \param[out] SA
77: *> \verbatim
78: *> SA is REAL array, dimension (LDSA,N)
79: *> Only the UPLO part of SA is referenced. On exit, if INFO=0,
80: *> the N-by-N coefficient matrix SA; if INFO>0, the content of
81: *> the UPLO part of SA is unspecified.
82: *> \endverbatim
83: *>
84: *> \param[in] LDSA
85: *> \verbatim
86: *> LDSA is INTEGER
87: *> The leading dimension of the array SA. LDSA >= max(1,M).
88: *> \endverbatim
89: *>
90: *> \param[out] INFO
91: *> \verbatim
92: *> INFO is INTEGER
93: *> = 0: successful exit.
94: *> = 1: an entry of the matrix A is greater than the SINGLE
95: *> PRECISION overflow threshold, in this case, the content
96: *> of the UPLO part of SA in exit is unspecified.
97: *> \endverbatim
98: *
99: * Authors:
100: * ========
101: *
1.13 bertrand 102: *> \author Univ. of Tennessee
103: *> \author Univ. of California Berkeley
104: *> \author Univ. of Colorado Denver
105: *> \author NAG Ltd.
1.7 bertrand 106: *
107: *> \ingroup doubleOTHERauxiliary
108: *
109: * =====================================================================
1.1 bertrand 110: SUBROUTINE DLAT2S( UPLO, N, A, LDA, SA, LDSA, INFO )
111: *
1.16 ! bertrand 112: * -- LAPACK auxiliary routine --
1.1 bertrand 113: * -- LAPACK is a software package provided by Univ. of Tennessee, --
114: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
115: *
116: * .. Scalar Arguments ..
117: CHARACTER UPLO
118: INTEGER INFO, LDA, LDSA, N
119: * ..
120: * .. Array Arguments ..
121: REAL SA( LDSA, * )
122: DOUBLE PRECISION A( LDA, * )
123: * ..
124: *
1.5 bertrand 125: * =====================================================================
1.1 bertrand 126: *
127: * .. Local Scalars ..
128: INTEGER I, J
129: DOUBLE PRECISION RMAX
130: LOGICAL UPPER
131: * ..
132: * .. External Functions ..
133: REAL SLAMCH
134: LOGICAL LSAME
135: EXTERNAL SLAMCH, LSAME
136: * ..
1.16 ! bertrand 137: * .. Intrinsic Functions ..
! 138: INTRINSIC REAL
! 139: * ..
1.1 bertrand 140: * .. Executable Statements ..
141: *
142: RMAX = SLAMCH( 'O' )
143: UPPER = LSAME( UPLO, 'U' )
144: IF( UPPER ) THEN
145: DO 20 J = 1, N
146: DO 10 I = 1, J
147: IF( ( A( I, J ).LT.-RMAX ) .OR. ( A( I, J ).GT.RMAX ) )
1.5 bertrand 148: $ THEN
1.1 bertrand 149: INFO = 1
150: GO TO 50
151: END IF
1.16 ! bertrand 152: SA( I, J ) = REAL( A( I, J ) )
1.1 bertrand 153: 10 CONTINUE
154: 20 CONTINUE
155: ELSE
156: DO 40 J = 1, N
157: DO 30 I = J, N
158: IF( ( A( I, J ).LT.-RMAX ) .OR. ( A( I, J ).GT.RMAX ) )
1.5 bertrand 159: $ THEN
1.1 bertrand 160: INFO = 1
161: GO TO 50
162: END IF
1.16 ! bertrand 163: SA( I, J ) = REAL( A( I, J ) )
1.1 bertrand 164: 30 CONTINUE
165: 40 CONTINUE
166: END IF
167: 50 CONTINUE
168: *
169: RETURN
170: *
171: * End of DLAT2S
172: *
173: END
CVSweb interface <joel.bertrand@systella.fr>
![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to dlat2s.f CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [local] / rpl / lapack / lapack