RE: [Help-glpk] Compiling GLPK for Java under Linux

[Meketon, Marc]

I suspect that the reason for the difference between the e+00 and e+000 is due to differences in how each compiler implemented printf, but not to any fundamental, underlying problem.

 

-Mrac

 

---

From: address@hidden [mailto:address@hidden On Behalf Of Sylvain Fournier
Sent: Tuesday, June 23, 2009 11:16 AM
To: Andrew Makhorin
Cc: address@hidden
Subject: Re: [Help-glpk] Compiling GLPK for Java under Linux

 

Thanks for the link, from now on I won't expect the same behavior for Windows and Linux when solving a linear model.
But what about the difference in the number of digits?

2009/6/23 Andrew Makhorin <address@hidden>

> I am getting back to this subject because I am facing a small
> problem using GLPK both on Windows and Linux.
> As I said in my previous e-mail, I managed to compile the library
> to use GLPK in java for Linux, and it works fine. However, I get a
> difference when running an instance under Windows on the one hand and
> on Linux on the other hand: it is the same optimal solution (same
> primal values for variables), but the basis is different, as well as
> the dual values of constraints and variables. It is a problem as I
> need to use these dual values in a Branch-and-Price algorithm to get
> new columns.

> During my investigation, I saw a difference that might be linked to
> this behaviour: when printing the solution into a file (using
> glp_print_sol), the Karush-Kuhn-Tucker optimality conditions (at the

> end) don #39;t provide exactly the same display. On the one hand

> (Linux), there are 2 digits for the powers of 10 (ex: 0.00e+00), and
> on the other hand (Windows), there are 3 (ex: 0.00e+000).
> Could the problem I am facing be linked to a rounding problem? If
> so, how can I make the result identical for Windows and Linux?
> If you need the model for which this problem occurs, feel free to ask.

Please see:
http://list.coin-or.org/pipermail/coin-discuss/2009-March/003548.html

 

 

----------------------------------------------------------------------------
This e-mail and any attachments may be confidential or legally privileged. If you received this message in error or are not the intended recipient, you should destroy the e-mail message and any attachments or copies, and you are prohibited from retaining, distributing, disclosing or using any information contained herein. Please inform us of the erroneous delivery by return e-mail.

Thank you for your cooperation.
----------------------------------------------------------------------------