Annotation of rpl/lapack/lapack/dlat2s.f, revision 1.7
1.7 ! bertrand 1: *> \brief \b DLAT2S
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: *> \htmlonly
! 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">
! 15: *> [TXT]</a>
! 16: *> \endhtmlonly
! 17: *
! 18: * Definition:
! 19: * ===========
! 20: *
! 21: * SUBROUTINE DLAT2S( UPLO, N, A, LDA, SA, LDSA, INFO )
! 22: *
! 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: * ..
! 31: *
! 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
! 43: *> RMAX. If not the convertion is aborted and a flag is raised.
! 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: *
! 102: *> \author Univ. of Tennessee
! 103: *> \author Univ. of California Berkeley
! 104: *> \author Univ. of Colorado Denver
! 105: *> \author NAG Ltd.
! 106: *
! 107: *> \date November 2011
! 108: *
! 109: *> \ingroup doubleOTHERauxiliary
! 110: *
! 111: * =====================================================================
1.1 bertrand 112: SUBROUTINE DLAT2S( UPLO, N, A, LDA, SA, LDSA, INFO )
113: *
1.7 ! bertrand 114: * -- LAPACK auxiliary routine (version 3.4.0) --
1.1 bertrand 115: * -- LAPACK is a software package provided by Univ. of Tennessee, --
116: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.7 ! bertrand 117: * November 2011
1.1 bertrand 118: *
119: * .. Scalar Arguments ..
120: CHARACTER UPLO
121: INTEGER INFO, LDA, LDSA, N
122: * ..
123: * .. Array Arguments ..
124: REAL SA( LDSA, * )
125: DOUBLE PRECISION A( LDA, * )
126: * ..
127: *
1.5 bertrand 128: * =====================================================================
1.1 bertrand 129: *
130: * .. Local Scalars ..
131: INTEGER I, J
132: DOUBLE PRECISION RMAX
133: LOGICAL UPPER
134: * ..
135: * .. External Functions ..
136: REAL SLAMCH
137: LOGICAL LSAME
138: EXTERNAL SLAMCH, LSAME
139: * ..
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
152: SA( I, J ) = A( I, J )
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
163: SA( I, J ) = A( I, J )
164: 30 CONTINUE
165: 40 CONTINUE
166: END IF
167: 50 CONTINUE
168: *
169: RETURN
170: *
171: * End of DLAT2S
172: *
173: END
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