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Annotation of rpl/lapack/lapack/dlag2s.f, revision 1.19

1.12      bertrand    1: *> \brief \b DLAG2S converts a double precision matrix to a single precision matrix.
1.10      bertrand    2: *
                      3: *  =========== DOCUMENTATION ===========
                      4: *
1.16      bertrand    5: * Online html documentation available at
                      6: *            http://www.netlib.org/lapack/explore-html/
1.10      bertrand    7: *
                      8: *> \htmlonly
1.16      bertrand    9: *> Download DLAG2S + dependencies
                     10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlag2s.f">
                     11: *> [TGZ]</a>
                     12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlag2s.f">
                     13: *> [ZIP]</a>
                     14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlag2s.f">
1.10      bertrand   15: *> [TXT]</a>
1.16      bertrand   16: *> \endhtmlonly
1.10      bertrand   17: *
                     18: *  Definition:
                     19: *  ===========
                     20: *
                     21: *       SUBROUTINE DLAG2S( M, N, A, LDA, SA, LDSA, INFO )
1.16      bertrand   22: *
1.10      bertrand   23: *       .. Scalar Arguments ..
                     24: *       INTEGER            INFO, LDA, LDSA, M, N
                     25: *       ..
                     26: *       .. Array Arguments ..
                     27: *       REAL               SA( LDSA, * )
                     28: *       DOUBLE PRECISION   A( LDA, * )
                     29: *       ..
1.16      bertrand   30: *
1.10      bertrand   31: *
                     32: *> \par Purpose:
                     33: *  =============
                     34: *>
                     35: *> \verbatim
                     36: *>
1.19    ! bertrand   37: *> DLAG2S converts a DOUBLE PRECISION matrix, A, to a SINGLE
        !            38: *> PRECISION matrix, SA.
1.10      bertrand   39: *>
                     40: *> RMAX is the overflow for the SINGLE PRECISION arithmetic
                     41: *> DLAG2S checks that all the entries of A are between -RMAX and
1.16      bertrand   42: *> RMAX. If not the conversion is aborted and a flag is raised.
1.10      bertrand   43: *>
                     44: *> This is an auxiliary routine so there is no argument checking.
                     45: *> \endverbatim
                     46: *
                     47: *  Arguments:
                     48: *  ==========
                     49: *
                     50: *> \param[in] M
                     51: *> \verbatim
                     52: *>          M is INTEGER
                     53: *>          The number of lines of the matrix A.  M >= 0.
                     54: *> \endverbatim
                     55: *>
                     56: *> \param[in] N
                     57: *> \verbatim
                     58: *>          N is INTEGER
                     59: *>          The number of columns of the matrix A.  N >= 0.
                     60: *> \endverbatim
                     61: *>
                     62: *> \param[in] A
                     63: *> \verbatim
                     64: *>          A is DOUBLE PRECISION array, dimension (LDA,N)
                     65: *>          On entry, the M-by-N coefficient matrix A.
                     66: *> \endverbatim
                     67: *>
                     68: *> \param[in] LDA
                     69: *> \verbatim
                     70: *>          LDA is INTEGER
                     71: *>          The leading dimension of the array A.  LDA >= max(1,M).
                     72: *> \endverbatim
                     73: *>
                     74: *> \param[out] SA
                     75: *> \verbatim
                     76: *>          SA is REAL array, dimension (LDSA,N)
                     77: *>          On exit, if INFO=0, the M-by-N coefficient matrix SA; if
                     78: *>          INFO>0, the content of SA is unspecified.
                     79: *> \endverbatim
                     80: *>
                     81: *> \param[in] LDSA
                     82: *> \verbatim
                     83: *>          LDSA is INTEGER
                     84: *>          The leading dimension of the array SA.  LDSA >= max(1,M).
                     85: *> \endverbatim
                     86: *>
                     87: *> \param[out] INFO
                     88: *> \verbatim
                     89: *>          INFO is INTEGER
                     90: *>          = 0:  successful exit.
                     91: *>          = 1:  an entry of the matrix A is greater than the SINGLE
                     92: *>                PRECISION overflow threshold, in this case, the content
                     93: *>                of SA in exit is unspecified.
                     94: *> \endverbatim
                     95: *
                     96: *  Authors:
                     97: *  ========
                     98: *
1.16      bertrand   99: *> \author Univ. of Tennessee
                    100: *> \author Univ. of California Berkeley
                    101: *> \author Univ. of Colorado Denver
                    102: *> \author NAG Ltd.
1.10      bertrand  103: *
                    104: *> \ingroup doubleOTHERauxiliary
                    105: *
                    106: *  =====================================================================
1.1       bertrand  107:       SUBROUTINE DLAG2S( M, N, A, LDA, SA, LDSA, INFO )
                    108: *
1.19    ! bertrand  109: *  -- LAPACK auxiliary routine --
1.1       bertrand  110: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
                    111: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
                    112: *
                    113: *     .. Scalar Arguments ..
                    114:       INTEGER            INFO, LDA, LDSA, M, N
                    115: *     ..
                    116: *     .. Array Arguments ..
                    117:       REAL               SA( LDSA, * )
                    118:       DOUBLE PRECISION   A( LDA, * )
                    119: *     ..
                    120: *
1.8       bertrand  121: *  =====================================================================
1.1       bertrand  122: *
                    123: *     .. Local Scalars ..
                    124:       INTEGER            I, J
                    125:       DOUBLE PRECISION   RMAX
                    126: *     ..
                    127: *     .. External Functions ..
                    128:       REAL               SLAMCH
                    129:       EXTERNAL           SLAMCH
                    130: *     ..
1.19    ! bertrand  131: *     .. Intrinsic Functions ..
        !           132:       INTRINSIC          REAL
        !           133: *     ..
1.1       bertrand  134: *     .. Executable Statements ..
                    135: *
                    136:       RMAX = SLAMCH( 'O' )
                    137:       DO 20 J = 1, N
                    138:          DO 10 I = 1, M
                    139:             IF( ( A( I, J ).LT.-RMAX ) .OR. ( A( I, J ).GT.RMAX ) ) THEN
                    140:                INFO = 1
                    141:                GO TO 30
                    142:             END IF
1.19    ! bertrand  143:             SA( I, J ) = REAL( A( I, J ) )
1.1       bertrand  144:    10    CONTINUE
                    145:    20 CONTINUE
                    146:       INFO = 0
                    147:    30 CONTINUE
                    148:       RETURN
                    149: *
                    150: *     End of DLAG2S
                    151: *
                    152:       END