Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris
 
PerlMonks  

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.


Comment on Re^5: Derangements iterator
Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://520145]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others wandering the Monastery: (14)
As of 2015-07-29 14:10 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









    Results (263 votes), past polls