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SUBROUTINE DLAT2S( UPLO, N, A, LDA, SA, LDSA, INFO )
*
* -- LAPACK PROTOTYPE auxiliary routine (version 3.1.2) --
* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
* May 2007
*
* .. Scalar Arguments ..
CHARACTER UPLO
INTEGER INFO, LDA, LDSA, N
* ..
* .. Array Arguments ..
REAL SA( LDSA, * )
DOUBLE PRECISION A( LDA, * )
* ..
*
* 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 convertion is aborted and a flag is raised.
*
* This is an auxiliary routine so there is no argument checking.
*
* Arguments
* =========
*
* UPLO (input) CHARACTER*1
* = 'U': A is upper triangular;
* = 'L': A is lower triangular.
*
* N (input) INTEGER
* The number of rows and columns of the matrix A. N >= 0.
*
* A (input) DOUBLE PRECISION array, dimension (LDA,N)
* On entry, the N-by-N triangular coefficient matrix A.
*
* LDA (input) INTEGER
* The leading dimension of the array A. LDA >= max(1,N).
*
* SA (output) 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.
*
* LDSA (input) INTEGER
* The leading dimension of the array SA. LDSA >= max(1,M).
*
* INFO (output) 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.
*
* =========
*
* .. 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
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