dlag2s.f

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*> \brief \b DLAG2S converts a double precision matrix to a single precision matrix.
*
*  =========== DOCUMENTATION ===========
*
* Online html documentation available at
*            http://www.netlib.org/lapack/explore-html/
*
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*
*  Definition:
*  ===========
*
*       SUBROUTINE DLAG2S( M, N, A, LDA, SA, LDSA, INFO )
*
*       .. Scalar Arguments ..
*       INTEGER            INFO, LDA, LDSA, M, N
*       ..
*       .. Array Arguments ..
*       REAL               SA( LDSA, * )
*       DOUBLE PRECISION   A( LDA, * )
*       ..
*
*
*> \par Purpose:
*  =============
*>
*> \verbatim
*>
*> DLAG2S converts a DOUBLE PRECISION matrix, A, to a SINGLE
*> PRECISION matrix, SA.
*>
*> RMAX is the overflow for the SINGLE PRECISION arithmetic
*> DLAG2S checks that all the entries of A are between -RMAX and
*> RMAX. If not the conversion is aborted and a flag is raised.
*>
*> This is an auxiliary routine so there is no argument checking.
*> \endverbatim
*
*  Arguments:
*  ==========
*
*> \param[in] M
*> \verbatim
*>          M is INTEGER
*>          The number of lines of the matrix A.  M >= 0.
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*>          N is INTEGER
*>          The number of columns of the matrix A.  N >= 0.
*> \endverbatim
*>
*> \param[in] A
*> \verbatim
*>          A is DOUBLE PRECISION array, dimension (LDA,N)
*>          On entry, the M-by-N coefficient matrix A.
*> \endverbatim
*>
*> \param[in] LDA
*> \verbatim
*>          LDA is INTEGER
*>          The leading dimension of the array A.  LDA >= max(1,M).
*> \endverbatim
*>
*> \param[out] SA
*> \verbatim
*>          SA is REAL array, dimension (LDSA,N)
*>          On exit, if INFO=0, the M-by-N coefficient matrix SA; if
*>          INFO>0, the content of SA is unspecified.
*> \endverbatim
*>
*> \param[in] LDSA
*> \verbatim
*>          LDSA is INTEGER
*>          The leading dimension of the array SA.  LDSA >= max(1,M).
*> \endverbatim
*>
*> \param[out] INFO
*> \verbatim
*>          INFO is INTEGER
*>          = 0:  successful exit.
*>          = 1:  an entry of the matrix A is greater than the SINGLE
*>                PRECISION overflow threshold, in this case, the content
*>                of SA in exit is unspecified.
*> \endverbatim
*
*  Authors:
*  ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \ingroup _lag2_
*
*  =====================================================================
      SUBROUTINE dlag2s( M, N, A, LDA, SA, LDSA, INFO )
*
*  -- LAPACK auxiliary routine --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
*     .. Scalar Arguments ..
      INTEGER            INFO, LDA, LDSA, M, N
*     ..
*     .. Array Arguments ..
      REAL               SA( LDSA, * )
      DOUBLE PRECISION   A( LDA, * )
*     ..
*
*  =====================================================================
*
*     .. Local Scalars ..
      INTEGER            I, J
      DOUBLE PRECISION   RMAX
*     ..
*     .. External Functions ..
      REAL               SLAMCH
      EXTERNAL           slamch
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          real
*     ..
*     .. Executable Statements ..
*
      rmax = slamch( 'O' )
      DO 20 j = 1, n
         DO 10 i = 1, m
            IF( ( a( i, j ).LT.-rmax ) .OR. ( a( i, j ).GT.rmax ) ) THEN
               info = 1
               GO TO 30
            END IF
            sa( i, j ) = real( a( i, j ) )
   10    CONTINUE
   20 CONTINUE
      info = 0
   30 CONTINUE
      RETURN
*
*     End of DLAG2S
*
      END