ft8d/shell.f90

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366 B
Fortran
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2018-03-24 07:20:34 -04:00
subroutine shell(n,a)
integer n
real a(n)
integer i,j,inc
real v
inc=1
1 inc=3*inc+1
if(inc.le.n) go to 1
2 inc=inc/3
do i=inc+1,n
v=a(i)
j=i
3 if(a(j-inc).gt.v) then
a(j)=a(j-inc)
j=j-inc
if(j.le.inc) go to 4
go to 3
endif
4 a(j)=v
enddo
if(inc.gt.1) go to 2
return
end subroutine shell