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Re: [Help-glpk] suffixes in mathprog
From: |
glpk xypron |
Subject: |
Re: [Help-glpk] suffixes in mathprog |
Date: |
Sun, 16 May 2010 23:35:08 +0200 |
Hello Andrew,
thanks for implementing suffixes in GLPK.
Some problems still have to be resolved:
== Compilation ==
The prerelease does not compile under Windows 32bit:
glpk_4_44.def : error LNK2001: unresolved external symbol _glp_ksp_mt1
glpk_4_44.def : error LNK2001: unresolved external symbol _glp_skpgen
Compilation was possilble after removing these symbols from the
definition file.
== Display statement ==
=== After solve ===
I tested by modifying examples/transp.mod
In glpk-4.43
solve;
display demand["Topeka"];
resulted in
Display statement at line 46
demand[Topeka] >= 275:
1 x[San-Diego,Topeka]
1 x[Seattle,Topeka]
In glpk-4.44 the output is
Display statement at line 46
275
I expect the display statement only to output the value of a
constraint when the suffix .val is appended.
In GLPK 4.44
solve;
display {i in I, j in J} x[i,j].dual;
results in
Display statement at line 45
x[Seattle,New-York].val = 50
x[Seattle,Chicago].val = 300
x[Seattle,Topeka].val = 0
x[San-Diego,New-York].val = 275
x[San-Diego,Chicago].val = 0
x[San-Diego,Topeka].val = 275
I expect the dual value to be output.
=== Before solve ===
In glpk-4.43 it was allowable to write:
display demand["Topeka"];
solve;
resulting in output
Display statement at line 44
demand[Topeka] >= 275:
1 x[San-Diego,Topeka]
1 x[Seattle,Topeka]
In glpk-4.44 an error occurs
..\examples\transp.mod:44: invalid reference to status, primal value, or dual
value of constraint de
mand above solve statement
Context: ...i in I } x [ i , j ] >= b [ j ] ; display demand [ '...' ] ;
In glpk-4.43 it was allowable to write:
display x;
solve;
resulting in
Display statement at line 44
x[Seattle,New-York] >= 0
x[Seattle,Chicago] >= 0
x[Seattle,Topeka] >= 0
x[San-Diego,New-York] >= 0
x[San-Diego,Chicago] >= 0
x[San-Diego,Topeka] >= 0
In glpk-4.44 an error occurs:
..\examples\transp.mod:44: invalid reference to variable x above solve statement
Context: ...in J } : sum { i in I } x [ i , j ] >= b [ j ] ; display x ;
MathProg model processing error
Best regards
Xypron
-------- Original-Nachricht --------
> Datum: Sun, 16 May 2010 13:11:19 +0400
> Betreff: [Help-glpk] suffixes in mathprog
> I have implemented the suffixes in MathProg.
>
> It would be nice if someone who is using this feature (due to Xypron)
> could test my implementation. The glpk tarball can be downloaded from
> http://sourceforge.net/projects/noumenon/files/ (please note that this
> is a non-official prerelease). Thanks.
>
> Andrew Makhorin
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