219 lines
5.2 KiB
Fortran
219 lines
5.2 KiB
Fortran
c-----------------------------------------------------------------------
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c\BeginDoc
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c
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c\Name: ssortr
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c
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c\Description:
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c Sort the array X1 in the order specified by WHICH and optionally
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c applies the permutation to the array X2.
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c
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c\Usage:
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c call ssortr
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c ( WHICH, APPLY, N, X1, X2 )
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c
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c\Arguments
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c WHICH Character*2. (Input)
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c 'LM' -> X1 is sorted into increasing order of magnitude.
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c 'SM' -> X1 is sorted into decreasing order of magnitude.
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c 'LA' -> X1 is sorted into increasing order of algebraic.
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c 'SA' -> X1 is sorted into decreasing order of algebraic.
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c
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c APPLY Logical. (Input)
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c APPLY = .TRUE. -> apply the sorted order to X2.
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c APPLY = .FALSE. -> do not apply the sorted order to X2.
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c
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c N Integer. (INPUT)
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c Size of the arrays.
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c
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c X1 Real array of length N. (INPUT/OUTPUT)
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c The array to be sorted.
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c
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c X2 Real array of length N. (INPUT/OUTPUT)
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c Only referenced if APPLY = .TRUE.
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c
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c\EndDoc
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c
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c-----------------------------------------------------------------------
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c
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c\BeginLib
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c
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c\Author
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c Danny Sorensen Phuong Vu
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c Richard Lehoucq CRPC / Rice University
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c Dept. of Computational & Houston, Texas
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c Applied Mathematics
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c Rice University
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c Houston, Texas
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c
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c\Revision history:
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c 12/16/93: Version ' 2.1'.
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c Adapted from the sort routine in LANSO.
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c
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c\SCCS Information: @(#)
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c FILE: sortr.F SID: 2.3 DATE OF SID: 4/19/96 RELEASE: 2
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c
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c\EndLib
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c
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c-----------------------------------------------------------------------
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c
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subroutine ssortr (which, apply, n, x1, x2)
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c
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c %------------------%
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c | Scalar Arguments |
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c %------------------%
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c
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character*2 which
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logical apply
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integer n
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c
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c %-----------------%
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c | Array Arguments |
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c %-----------------%
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c
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Real
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& x1(0:n-1), x2(0:n-1)
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c
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c %---------------%
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c | Local Scalars |
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c %---------------%
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c
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integer i, igap, j
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Real
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& temp
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c
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c %-----------------------%
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c | Executable Statements |
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c %-----------------------%
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c
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igap = n / 2
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c
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if (which .eq. 'SA') then
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c
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c X1 is sorted into decreasing order of algebraic.
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c
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10 continue
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if (igap .eq. 0) go to 9000
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do 30 i = igap, n-1
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j = i-igap
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20 continue
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c
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if (j.lt.0) go to 30
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c
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if (x1(j).lt.x1(j+igap)) then
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temp = x1(j)
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x1(j) = x1(j+igap)
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x1(j+igap) = temp
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if (apply) then
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temp = x2(j)
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x2(j) = x2(j+igap)
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x2(j+igap) = temp
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end if
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else
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go to 30
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endif
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j = j-igap
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go to 20
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30 continue
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igap = igap / 2
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go to 10
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c
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else if (which .eq. 'SM') then
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c
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c X1 is sorted into decreasing order of magnitude.
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c
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40 continue
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if (igap .eq. 0) go to 9000
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do 60 i = igap, n-1
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j = i-igap
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50 continue
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c
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if (j.lt.0) go to 60
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c
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if (abs(x1(j)).lt.abs(x1(j+igap))) then
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temp = x1(j)
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x1(j) = x1(j+igap)
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x1(j+igap) = temp
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if (apply) then
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temp = x2(j)
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x2(j) = x2(j+igap)
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x2(j+igap) = temp
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end if
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else
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go to 60
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endif
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j = j-igap
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go to 50
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60 continue
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igap = igap / 2
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go to 40
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c
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else if (which .eq. 'LA') then
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c
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c X1 is sorted into increasing order of algebraic.
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c
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70 continue
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if (igap .eq. 0) go to 9000
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do 90 i = igap, n-1
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j = i-igap
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80 continue
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c
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if (j.lt.0) go to 90
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c
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if (x1(j).gt.x1(j+igap)) then
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temp = x1(j)
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x1(j) = x1(j+igap)
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x1(j+igap) = temp
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if (apply) then
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temp = x2(j)
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x2(j) = x2(j+igap)
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x2(j+igap) = temp
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end if
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else
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go to 90
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endif
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j = j-igap
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go to 80
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90 continue
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igap = igap / 2
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go to 70
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c
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else if (which .eq. 'LM') then
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c
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c X1 is sorted into increasing order of magnitude.
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c
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100 continue
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if (igap .eq. 0) go to 9000
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do 120 i = igap, n-1
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j = i-igap
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110 continue
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c
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if (j.lt.0) go to 120
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c
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if (abs(x1(j)).gt.abs(x1(j+igap))) then
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temp = x1(j)
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x1(j) = x1(j+igap)
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x1(j+igap) = temp
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if (apply) then
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temp = x2(j)
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x2(j) = x2(j+igap)
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x2(j+igap) = temp
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end if
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else
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go to 120
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endif
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j = j-igap
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go to 110
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120 continue
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igap = igap / 2
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go to 100
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end if
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c
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9000 continue
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return
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c
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c %---------------%
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c | End of ssortr |
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c %---------------%
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c
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end
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