Re: [Help-glpk] 4.48 vs 4.47

[Haroldo Santos]

glp_read_lp can be one of the causes:
The order of the variables can affect the number of simplex iterations - the index of the variable can be used to break ties in selecting the next variable to enter the base.

But it appears that this is a more complex issue: the processing time increased more than one time (a lot) as new GLPK versions appeared...

On Tue, Mar 12, 2013 at 9:05 PM, Patrik Dufresne <address@hidden> wrote:

Hi,

May someone give me an explanation about why the same problem run with glpk 4.38 is faster then glpk 4.47 ?

GLPK Version	Iteration	Time used
4.37	6507	3.6 secs
4.38	6496	5.5 secs
4.39	23708	22.1 secs
4.40	23708	22.1 secs
4.41	23708	23.6 secs
4.42	45540	64.6 secs
4.43	45540	64.4 secs
4.44	45540	60.7 secs
4.45	45540	60.3 secs
4.46	45540	61.5 secs
4.47	45540	61.0 secs

Run with

./glpsol --intopt --fpump --cpxlp min-all-swappable-task1

See my dropbox for all the results and the problem file

https://www.dropbox.com/sh/ja2myngas5lorow/oUTkkFxW5N/glpk-438-vs439

Looking at the change log, the only related modification I see that may impact the number of iteration if the reimplementation of glp_read_lp(). Thanks for your comments.

Patrik Dufresne

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-- 
=============================================================
Haroldo Gambini Santos
Computing Department
Universidade Federal de Ouro Preto - UFOP
email: haroldo [at ] iceb.ufop.br
home/research page: www.decom.ufop.br/haroldo