dlat2s()

subroutine dlat2s	(	character	uplo,
		integer	n,
		double precision, dimension( lda, * )	a,
		integer	lda,
		real, dimension( ldsa, * )	sa,
		integer	ldsa,
		integer	info )

DLAT2S converts a double-precision triangular matrix to a single-precision triangular matrix.

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Purpose:

!>
!> 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.
!> 

Parameters

[in]	UPLO	!> UPLO is CHARACTER*1 !> = 'U': A is upper triangular; !> = 'L': A is lower triangular. !>
[in]	N	!> N is INTEGER !> The number of rows and columns of the matrix A. N >= 0. !>
[in]	A	!> A is DOUBLE PRECISION array, dimension (LDA,N) !> On entry, the N-by-N triangular coefficient matrix A. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
[out]	SA	!> 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. !>
[in]	LDSA	!> LDSA is INTEGER !> The leading dimension of the array SA. LDSA >= max(1,M). !>
[out]	INFO	!> 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. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 108 of file dlat2s.f.

*
*  -- 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
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          real
*     ..
*     .. 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 ) = real( 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 ) = real( a( i, j ) )
   30       CONTINUE
   40    CONTINUE
      END IF
   50 CONTINUE
*
      RETURN
*
*     End of DLAT2S
*

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