[Octave-bug-tracker] [bug #31709] simple routine which runs 20 times slower on octave vs. matlab!

[kody law]

URL:
  <http://savannah.gnu.org/bugs/?31709>

                 Summary: simple routine which runs 20 times slower on octave
vs. matlab!
                 Project: GNU Octave
            Submitted by: kodo
            Submitted on: Fri 19 Nov 2010 10:52:14 PM GMT
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.2.3
        Operating System: Mac OS

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Details:

The peculiarity is attached.  Any suggestions about how to speed it up would
be greatly appreciated.  Thanks a lot for all your help!

A takes about 2.5 seconds on matlab, while B takes 2 seconds.  On octave the
difference is more than an order of magnitude!

%%%% when A is uncommented and B is commented, 
%%%% the routine takes 40 secs!

%%%% when B is uncommented and A is commented, 
%%%% the routine takes 2 secs!

%%%% each time, the program sorts a permutation into
%%%% cycles, going through each element.  'lens' lists 
%%%% the number of elements in permutations of each length

%%%% longer permutations = 
%%%% fewer entries into while loop =
%%%% faster -- too much faster!

Thanks again, best



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File Attachments:


-------------------------------------------------------
Date: Fri 19 Nov 2010 10:52:14 PM GMT  Name: per.tar  Size: 103kB   By: kodo

<http://savannah.gnu.org/bugs/download.php?file_id=22064>

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