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Re^5: Derangements iterator

by Jedaļ (Initiate)
on Dec 31, 2005 at 13:34 UTC ( #520145=note: print w/replies, xml ) Need Help??

in reply to Re^4: Derangements iterator
in thread Derangements iterator

Oops.. Sorry, the wrapper performs unnecessary operations, here a good version :
use Inline C => <<'END_OF_C_CODE'; void cderange ( SV* truc, ... ){ SV* sv_temp; I32 index, i; Inline_Stack_Vars; srand(time( NULL )); index = Inline_Stack_Items; for (; index; index--) { i = (I32) (rand() % (index)); sv_temp = Inline_Stack_Item(index); Inline_Stack_Item(index) = Inline_Stack_Item(i); Inline_Stack_Item(i) = sv_temp; } Inline_Stack_Done; } END_OF_C_CODE
Very fast, but this code is subject to the same caveat as Algorithm::Numerical::Shuffle.

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