*> \brief \b DLAT2S converts a double-precision triangular matrix to a single-precision triangular matrix. * * =========== DOCUMENTATION =========== * * Online html documentation available at * http://www.netlib.org/lapack/explore-html/ * *> \htmlonly *> Download DLAT2S + dependencies *> *> [TGZ] *> *> [ZIP] *> *> [TXT] *> \endhtmlonly * * Definition: * =========== * * SUBROUTINE DLAT2S( UPLO, N, A, LDA, SA, LDSA, INFO ) * * .. Scalar Arguments .. * CHARACTER UPLO * INTEGER INFO, LDA, LDSA, N * .. * .. Array Arguments .. * REAL SA( LDSA, * ) * DOUBLE PRECISION A( LDA, * ) * .. * * *> \par Purpose: * ============= *> *> \verbatim *> *> DLAT2S converts a DOUBLE PRECISION triangular matrix, SA, to a SINGLE *> PRECISION triangular matrix, A. *> *> RMAX is the overflow for the SINGLE PRECISION arithmetic *> DLAS2S 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] UPLO *> \verbatim *> UPLO is CHARACTER*1 *> = 'U': A is upper triangular; *> = 'L': A is lower triangular. *> \endverbatim *> *> \param[in] N *> \verbatim *> N is INTEGER *> The number of rows and columns of the matrix A. N >= 0. *> \endverbatim *> *> \param[in] A *> \verbatim *> A is DOUBLE PRECISION array, dimension (LDA,N) *> On entry, the N-by-N triangular coefficient matrix A. *> \endverbatim *> *> \param[in] LDA *> \verbatim *> LDA is INTEGER *> The leading dimension of the array A. LDA >= max(1,N). *> \endverbatim *> *> \param[out] SA *> \verbatim *> SA is REAL array, dimension (LDSA,N) *> Only the UPLO part of SA is referenced. On exit, if INFO=0, *> the N-by-N coefficient matrix SA; if INFO>0, the content of *> the UPLO part 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 the UPLO part 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 doubleOTHERauxiliary * * ===================================================================== SUBROUTINE DLAT2S( UPLO, 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 .. CHARACTER UPLO INTEGER INFO, LDA, LDSA, N * .. * .. Array Arguments .. REAL SA( LDSA, * ) DOUBLE PRECISION A( LDA, * ) * .. * * ===================================================================== * * .. Local Scalars .. INTEGER I, J DOUBLE PRECISION RMAX LOGICAL UPPER * .. * .. External Functions .. REAL SLAMCH LOGICAL LSAME EXTERNAL SLAMCH, LSAME * .. * .. Executable Statements .. * RMAX = SLAMCH( 'O' ) UPPER = LSAME( UPLO, 'U' ) IF( UPPER ) THEN DO 20 J = 1, N DO 10 I = 1, J IF( ( A( I, J ).LT.-RMAX ) .OR. ( A( I, J ).GT.RMAX ) ) $ THEN INFO = 1 GO TO 50 END IF SA( I, J ) = A( I, J ) 10 CONTINUE 20 CONTINUE ELSE DO 40 J = 1, N DO 30 I = J, N IF( ( A( I, J ).LT.-RMAX ) .OR. ( A( I, J ).GT.RMAX ) ) $ THEN INFO = 1 GO TO 50 END IF SA( I, J ) = A( I, J ) 30 CONTINUE 40 CONTINUE END IF 50 CONTINUE * RETURN * * End of DLAT2S * END