numeric-linalg

001
002
003
004
005
006
007
008
009
010
011
012
013
014
015
016
017
018
019
020
021
022
023
024
025
026
027
028
029
030
031
032
033
034
035
036
037
038
039
040
041
042
043
044
045
046
047
048
049
050
051
052
053
054
055
056
057
058
059
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
089
090
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168

*> \brief \b SLAMRG 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 SLAMRG + dependencies
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slamrg.f">
*> [TGZ]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slamrg.f">
*> [ZIP]</a>
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slamrg.f">
*> [TXT]</a>
*> \endhtmlonly
*
*  Definition:
*  ===========
*
*       SUBROUTINE SLAMRG( N1, N2, A, STRD1, STRD2, INDEX )
*
*       .. Scalar Arguments ..
*       INTEGER            N1, N2, STRD1, STRD2
*       ..
*       .. Array Arguments ..
*       INTEGER            INDEX( * )
*       REAL               A( * )
*       ..
*
*
*> \par Purpose:
*  =============
*>
*> \verbatim
*>
*> SLAMRG 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 REAL 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] STRD1
*> \verbatim
*>          STRD1 is INTEGER
*> \endverbatim
*>
*> \param[in] STRD2
*> \verbatim
*>          STRD2 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 (STRDx = 1) or descending
*>         (STRDx = -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.
*
*> \ingroup lamrg
*
*  =====================================================================
      SUBROUTINE SLAMRG( N1, N2, A, STRD1, STRD2, INDEX )
*
*  -- LAPACK computational routine --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
*     .. Scalar Arguments ..
      INTEGER            N1, N2, STRD1, STRD2
*     ..
*     .. Array Arguments ..
      INTEGER            INDEX( * )
      REAL               A( * )
*     ..
*
*  =====================================================================
*
*     .. Local Scalars ..
      INTEGER            I, IND1, IND2, N1SV, N2SV
*     ..
*     .. Executable Statements ..
*
      N1SV = N1
      N2SV = N2
      IF( STRD1.GT.0 ) THEN
         IND1 = 1
      ELSE
         IND1 = N1
      END IF
      IF( STRD2.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 + STRD1
            N1SV = N1SV - 1
         ELSE
            INDEX( I ) = IND2
            I = I + 1
            IND2 = IND2 + STRD2
            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 + STRD2
   20    CONTINUE
      ELSE
*     N2SV .EQ. 0
         DO 30 N2SV = 1, N1SV
            INDEX( I ) = IND1
            I = I + 1
            IND1 = IND1 + STRD1
   30    CONTINUE
      END IF
*
      RETURN
*
*     End of SLAMRG
*
      END