[Bug-gsl] [bug #51104] gsl_permutation_next efficiency

[Patrick Alken]

URL:
  <http://savannah.gnu.org/bugs/?51104>

                 Summary: gsl_permutation_next efficiency
                 Project: GNU Scientific Library
            Submitted by: psa
            Submitted on: Wed 24 May 2017 08:45:59 AM UTC
                Category: Performance
                Severity: 3 - Normal
        Operating System: 
                  Status: None
             Assigned to: None
             Open/Closed: Open
                 Release: 
         Discussion Lock: Any

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Details:

from pgsinitsyn =at= gmail =dot= com

Hello everyone,

I was reading the permutation module of GSL and found that a function
"gsl_permutation_next" can be improved (you can see function
gsl_permutation_next0
<https://gist.github.com/pgsin/fc779f7ce7d4724221fe2dc5450e9358#file-gsl_permutation_next-test-c-L111>,
more specifically - this line
<https://gist.github.com/pgsin/fc779f7ce7d4724221fe2dc5450e9358#file-gsl_permutation_next-test-c-L135>
).

I made a benchmarking on my computer (AMD Opteron(TM) Processor 6276; gcc
-O2; gcc Ubuntu 4.8.4-2ubuntu1~14.04.3) and found a significant difference
in the performance (result contains stdout; bencmark.pdf - visualisation).

Best,
Pavel Sinitcyn



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File Attachments:


-------------------------------------------------------
Date: Wed 24 May 2017 08:45:59 AM UTC  Name: benchmark.pdf  Size: 6kB   By:
psa

<http://savannah.gnu.org/bugs/download.php?file_id=40775>
-------------------------------------------------------
Date: Wed 24 May 2017 08:45:59 AM UTC  Name: result.txt  Size: 2kB   By: psa

<http://savannah.gnu.org/bugs/download.php?file_id=40776>

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