18 lines
382 B
Fortran
18 lines
382 B
Fortran
FUNCTION igray(n,is)
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INTEGER igray,is,n
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INTEGER idiv,ish
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if (is.ge.0) then
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igray=ieor(n,n/2)
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else
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ish=-1
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igray=n
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1 continue
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idiv=ishft(igray,ish)
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igray=ieor(igray,idiv)
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if(idiv.le.1.or.ish.eq.-16)return
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ish=ish+ish
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goto 1
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endif
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return
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END
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