You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
103 lines
2.5 KiB
103 lines
2.5 KiB
2 years ago
|
C Copyright(C) 1999-2020 National Technology & Engineering Solutions
|
||
|
|
C of Sandia, LLC (NTESS). Under the terms of Contract DE-NA0003525 with
|
||
|
|
C NTESS, the U.S. Government retains certain rights in this software.
|
||
|
|
C
|
||
|
|
C See packages/seacas/LICENSE for details
|
||
|
|
|
||
|
|
c$$$ program test
|
||
|
|
c$$$ parameter (n=20)
|
||
|
|
c$$$ dimension a(n)
|
||
|
|
c$$$ integer indx(n)
|
||
|
|
c$$$
|
||
|
|
c$$$ integer*4 seed
|
||
|
|
c$$$ seed=0
|
||
|
|
c$$$
|
||
|
|
c$$$ call srand(time())
|
||
|
|
c$$$ do i=1, n
|
||
|
|
c$$$ a(i) = rand(seed)
|
||
|
|
c$$$ end do
|
||
|
|
c$$$
|
||
|
|
c$$$ do i=1,n
|
||
|
|
c$$$ write (*,*) a(i)
|
||
|
|
c$$$ end do
|
||
|
|
c$$$ write (*,*) '-------'
|
||
|
|
c$$$
|
||
|
|
c$$$ call indexx(a, indx, n, .true.)
|
||
|
|
c$$$
|
||
|
|
c$$$ do i=1,n
|
||
|
|
c$$$ write (*,*) i, indx(i), a(indx(i))
|
||
|
|
c$$$ end do
|
||
|
|
c$$$
|
||
|
|
c$$$ end
|
||
|
|
|
||
|
|
C------------------------------------------------------------------------
|
||
|
|
C SUBROUTINE INDEXX: Indexes an array ARRAY, that is
|
||
|
|
C it outputs an array INDX such that ARRAY(INDX(J)) is in
|
||
|
|
C ascending order for J=1,2,...,N. The input quantities N and
|
||
|
|
C ARRAY are not changed.
|
||
|
|
|
||
|
|
C ARRAY (*) - Array to be sorted
|
||
|
|
C INDX (modified) - Sorted order of ARRAY
|
||
|
|
C N - Number of elements in ARRAY
|
||
|
|
C INIT - .FALSE. if INDX already setup
|
||
|
|
C .TRUE. if INDX must be initialized
|
||
|
|
C------------------------------------------------------------------------
|
||
|
|
|
||
|
|
subroutine indexx(a, indx, n, init)
|
||
|
|
|
||
|
|
dimension a(*)
|
||
|
|
integer indx(0:*)
|
||
|
|
integer n
|
||
|
|
logical init
|
||
|
|
|
||
|
|
integer start, bottom
|
||
|
|
integer temp
|
||
|
|
|
||
|
|
if (init) then
|
||
|
|
do i=1, n
|
||
|
|
indx(i-1) = i
|
||
|
|
end do
|
||
|
|
end if
|
||
|
|
|
||
|
|
do start = (n-2)/2, 0, -1
|
||
|
|
call my_siftdown(a, indx, start, n)
|
||
|
|
end do
|
||
|
|
|
||
|
|
do bottom = n-1, 1, -1
|
||
|
|
temp = indx(0)
|
||
|
|
indx(0) = indx(bottom)
|
||
|
|
indx(bottom) = temp
|
||
|
|
call my_siftdown(a, indx, 0, bottom)
|
||
|
|
end do
|
||
|
|
end
|
||
|
|
|
||
|
|
subroutine my_siftdown(a, indx, start, bottom)
|
||
|
|
|
||
|
|
real a(*)
|
||
|
|
integer indx(0:*)
|
||
|
|
|
||
|
|
integer start, bottom
|
||
|
|
integer child, root
|
||
|
|
integer temp
|
||
|
|
|
||
|
|
root = start
|
||
|
|
do while(root*2 + 1 .lt. bottom)
|
||
|
|
child = root * 2 + 1
|
||
|
|
|
||
|
|
if ((child + 1 .lt. bottom) .and.
|
||
|
|
* (a(indx(child)) .lt. a(indx(child+1)))) then
|
||
|
|
child = child + 1
|
||
|
|
end if
|
||
|
|
|
||
|
|
if (a(indx(root)) .lt. a(indx(child))) then
|
||
|
|
temp = indx(child)
|
||
|
|
indx(child) = indx(root)
|
||
|
|
indx(root) = temp
|
||
|
|
root = child
|
||
|
|
else
|
||
|
|
return
|
||
|
|
end if
|
||
|
|
end do
|
||
|
|
return
|
||
|
|
end
|