forked from lijiext/lammps
172 lines
4.4 KiB
Fortran
172 lines
4.4 KiB
Fortran
*> \brief \b DLAMRG creates a permutation list to merge the entries of two independently sorted sets into a single set sorted in ascending order.
|
|
*
|
|
* =========== DOCUMENTATION ===========
|
|
*
|
|
* Online html documentation available at
|
|
* http://www.netlib.org/lapack/explore-html/
|
|
*
|
|
*> \htmlonly
|
|
*> Download DLAMRG + dependencies
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlamrg.f">
|
|
*> [TGZ]</a>
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlamrg.f">
|
|
*> [ZIP]</a>
|
|
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlamrg.f">
|
|
*> [TXT]</a>
|
|
*> \endhtmlonly
|
|
*
|
|
* Definition:
|
|
* ===========
|
|
*
|
|
* SUBROUTINE DLAMRG( N1, N2, A, DTRD1, DTRD2, INDEX )
|
|
*
|
|
* .. Scalar Arguments ..
|
|
* INTEGER DTRD1, DTRD2, N1, N2
|
|
* ..
|
|
* .. Array Arguments ..
|
|
* INTEGER INDEX( * )
|
|
* DOUBLE PRECISION A( * )
|
|
* ..
|
|
*
|
|
*
|
|
*> \par Purpose:
|
|
* =============
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*> DLAMRG will create a permutation list which will merge the elements
|
|
*> of A (which is composed of two independently sorted sets) into a
|
|
*> single set which is sorted in ascending order.
|
|
*> \endverbatim
|
|
*
|
|
* Arguments:
|
|
* ==========
|
|
*
|
|
*> \param[in] N1
|
|
*> \verbatim
|
|
*> N1 is INTEGER
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] N2
|
|
*> \verbatim
|
|
*> N2 is INTEGER
|
|
*> These arguments contain the respective lengths of the two
|
|
*> sorted lists to be merged.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] A
|
|
*> \verbatim
|
|
*> A is DOUBLE PRECISION array, dimension (N1+N2)
|
|
*> The first N1 elements of A contain a list of numbers which
|
|
*> are sorted in either ascending or descending order. Likewise
|
|
*> for the final N2 elements.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] DTRD1
|
|
*> \verbatim
|
|
*> DTRD1 is INTEGER
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] DTRD2
|
|
*> \verbatim
|
|
*> DTRD2 is INTEGER
|
|
*> These are the strides to be taken through the array A.
|
|
*> Allowable strides are 1 and -1. They indicate whether a
|
|
*> subset of A is sorted in ascending (DTRDx = 1) or descending
|
|
*> (DTRDx = -1) order.
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[out] INDEX
|
|
*> \verbatim
|
|
*> INDEX is INTEGER array, dimension (N1+N2)
|
|
*> On exit this array will contain a permutation such that
|
|
*> if B( I ) = A( INDEX( I ) ) for I=1,N1+N2, then B will be
|
|
*> sorted in ascending order.
|
|
*> \endverbatim
|
|
*
|
|
* Authors:
|
|
* ========
|
|
*
|
|
*> \author Univ. of Tennessee
|
|
*> \author Univ. of California Berkeley
|
|
*> \author Univ. of Colorado Denver
|
|
*> \author NAG Ltd.
|
|
*
|
|
*> \date June 2016
|
|
*
|
|
*> \ingroup auxOTHERcomputational
|
|
*
|
|
* =====================================================================
|
|
SUBROUTINE DLAMRG( N1, N2, A, DTRD1, DTRD2, INDEX )
|
|
*
|
|
* -- LAPACK computational routine (version 3.7.0) --
|
|
* -- LAPACK is a software package provided by Univ. of Tennessee, --
|
|
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
|
* June 2016
|
|
*
|
|
* .. Scalar Arguments ..
|
|
INTEGER DTRD1, DTRD2, N1, N2
|
|
* ..
|
|
* .. Array Arguments ..
|
|
INTEGER INDEX( * )
|
|
DOUBLE PRECISION A( * )
|
|
* ..
|
|
*
|
|
* =====================================================================
|
|
*
|
|
* .. Local Scalars ..
|
|
INTEGER I, IND1, IND2, N1SV, N2SV
|
|
* ..
|
|
* .. Executable Statements ..
|
|
*
|
|
N1SV = N1
|
|
N2SV = N2
|
|
IF( DTRD1.GT.0 ) THEN
|
|
IND1 = 1
|
|
ELSE
|
|
IND1 = N1
|
|
END IF
|
|
IF( DTRD2.GT.0 ) THEN
|
|
IND2 = 1 + N1
|
|
ELSE
|
|
IND2 = N1 + N2
|
|
END IF
|
|
I = 1
|
|
* while ( (N1SV > 0) & (N2SV > 0) )
|
|
10 CONTINUE
|
|
IF( N1SV.GT.0 .AND. N2SV.GT.0 ) THEN
|
|
IF( A( IND1 ).LE.A( IND2 ) ) THEN
|
|
INDEX( I ) = IND1
|
|
I = I + 1
|
|
IND1 = IND1 + DTRD1
|
|
N1SV = N1SV - 1
|
|
ELSE
|
|
INDEX( I ) = IND2
|
|
I = I + 1
|
|
IND2 = IND2 + DTRD2
|
|
N2SV = N2SV - 1
|
|
END IF
|
|
GO TO 10
|
|
END IF
|
|
* end while
|
|
IF( N1SV.EQ.0 ) THEN
|
|
DO 20 N1SV = 1, N2SV
|
|
INDEX( I ) = IND2
|
|
I = I + 1
|
|
IND2 = IND2 + DTRD2
|
|
20 CONTINUE
|
|
ELSE
|
|
* N2SV .EQ. 0
|
|
DO 30 N2SV = 1, N1SV
|
|
INDEX( I ) = IND1
|
|
I = I + 1
|
|
IND1 = IND1 + DTRD1
|
|
30 CONTINUE
|
|
END IF
|
|
*
|
|
RETURN
|
|
*
|
|
* End of DLAMRG
|
|
*
|
|
END
|