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*> \brief \b DLAORD
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* SUBROUTINE DLAORD( JOB, N, X, INCX )
*
* .. Scalar Arguments ..
* CHARACTER JOB
* INTEGER INCX, N
* ..
* .. Array Arguments ..
* DOUBLE PRECISION X( * )
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> DLAORD sorts the elements of a vector x in increasing or decreasing
*> order.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] JOB
*> \verbatim
*> JOB is CHARACTER
*> = 'I': Sort in increasing order
*> = 'D': Sort in decreasing order
*> \endverbatim
*>
*> \param[in] N
*> \verbatim
*> N is INTEGER
*> The length of the vector X.
*> \endverbatim
*>
*> \param[in,out] X
*> \verbatim
*> X is DOUBLE PRECISION array, dimension
*> (1+(N-1)*INCX)
*> On entry, the vector of length n to be sorted.
*> On exit, the vector x is sorted in the prescribed order.
*> \endverbatim
*>
*> \param[in] INCX
*> \verbatim
*> INCX is INTEGER
*> The spacing between successive elements of X. INCX >= 0.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup double_lin
*
* =====================================================================
SUBROUTINE DLAORD( JOB, N, X, INCX )
*
* -- LAPACK test routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
CHARACTER JOB
INTEGER INCX, N
* ..
* .. Array Arguments ..
DOUBLE PRECISION X( * )
* ..
*
* =====================================================================
*
* .. Local Scalars ..
INTEGER I, INC, IX, IXNEXT
DOUBLE PRECISION TEMP
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS
* ..
* .. Executable Statements ..
*
INC = ABS( INCX )
IF( LSAME( JOB, 'I' ) ) THEN
*
* Sort in increasing order
*
DO 20 I = 2, N
IX = 1 + ( I-1 )*INC
10 CONTINUE
IF( IX.EQ.1 )
$ GO TO 20
IXNEXT = IX - INC
IF( X( IX ).GT.X( IXNEXT ) ) THEN
GO TO 20
ELSE
TEMP = X( IX )
X( IX ) = X( IXNEXT )
X( IXNEXT ) = TEMP
END IF
IX = IXNEXT
GO TO 10
20 CONTINUE
*
ELSE IF( LSAME( JOB, 'D' ) ) THEN
*
* Sort in decreasing order
*
DO 40 I = 2, N
IX = 1 + ( I-1 )*INC
30 CONTINUE
IF( IX.EQ.1 )
$ GO TO 40
IXNEXT = IX - INC
IF( X( IX ).LT.X( IXNEXT ) ) THEN
GO TO 40
ELSE
TEMP = X( IX )
X( IX ) = X( IXNEXT )
X( IXNEXT ) = TEMP
END IF
IX = IXNEXT
GO TO 30
40 CONTINUE
END IF
RETURN
*
* End of DLAORD
*
END
|
