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[Bug-glpk] Difference, 32bit build - 64bit build
From: |
Christoph Cullmann |
Subject: |
[Bug-glpk] Difference, 32bit build - 64bit build |
Date: |
Wed, 24 Sep 2008 20:15:19 +0200 |
User-agent: |
KMail/1.10.1 (Linux/2.6.27-2-generic; KDE/4.1.1; x86_64; ; ) |
Hi,
I have a difference with solving a larger problem on 32bit and 64bit linux,
libglpk 4.31 build from tarball, no patches, gcc-4.1, no fancy optimizations,
-O0.
On 32bit, I get:
address@hidden:/local/cullmann/build/libglpk.default/usr/bin$ ./glpsol --cpxlp
~/value_15318949093.lp
glp_read_lp: reading problem data from `/home/cullmann/value_15318949093.lp'...
glp_read_lp: 1015 rows, 1577 columns, 3513 non-zeros
glp_read_lp: 1577 integer columns, none of which are binary
glp_read_lp: 2949 lines were read
glp_simplex: original LP has 1015 rows, 1577 columns, 3513 non-zeros
glp_simplex: presolved LP has 712 rows, 874 columns, 1942 non-zeros
Scaling...
A: min|aij| = 1.000e+00 max|aij| = 6.000e+00 ratio = 6.000e+00
Problem data seem to be well scaled
Crashing...
Size of triangular part = 666
0: obj = 1.877000000e+03 infeas = 2.400e+01 (46)
* 3: obj = 1.877000000e+03 infeas = 0.000e+00 (46)
* 200: obj = 1.383603996e+10 infeas = 0.000e+00 (0)
* 400: obj = 1.495135855e+10 infeas = 0.000e+00 (0)
* 558: obj = 1.531894909e+10 infeas = 0.000e+00 (0)
OPTIMAL SOLUTION FOUND
Integer optimization begins...
+ 558: mip = not found yet <= +inf (1; 0)
+ 558: mip = not found yet <= tree is empty (0; 1)
PROBLEM HAS NO INTEGER FEASIBLE SOLUTION
While on 64bit, the same problem yields a solution:
address@hidden:/local/cullmann/build/glpsolve.default/usr/bin$ ./glpsol --cpxlp
~/value_15318949093.lp
glp_read_lp: reading problem data from `/home/cullmann/value_15318949093.lp'...
glp_read_lp: 1015 rows, 1577 columns, 3513 non-zeros
glp_read_lp: 1577 integer columns, none of which are binary
glp_read_lp: 2949 lines were read
glp_simplex: original LP has 1015 rows, 1577 columns, 3513 non-zeros
glp_simplex: presolved LP has 712 rows, 874 columns, 1942 non-zeros
Scaling...
A: min|aij| = 1.000e+00 max|aij| = 6.000e+00 ratio = 6.000e+00
Problem data seem to be well scaled
Crashing...
Size of triangular part = 666
0: obj = 1.877000000e+03 infeas = 2.400e+01 (46)
* 3: obj = 1.877000000e+03 infeas = 0.000e+00 (46)
* 200: obj = 1.383603996e+10 infeas = 0.000e+00 (0)
* 400: obj = 1.495135855e+10 infeas = 0.000e+00 (0)
* 559: obj = 1.531894909e+10 infeas = 0.000e+00 (0)
OPTIMAL SOLUTION FOUND
Integer optimization begins...
+ 559: mip = not found yet <= +inf (1; 0)
+ 559: >>>>> 1.531894909e+10 <= 1.531894909e+10 0.0% (1; 0)
+ 559: mip = 1.531894909e+10 <= tree is empty 0.0% (0; 1)
INTEGER OPTIMAL SOLUTION FOUND
Time used: 0.1 secs
Memory used: 1.3 Mb (1400268 bytes)
I have verified the 64bit solution using CPLEX, which yields the same value.
Any ideas, what this might cause?
Interesting sidenote: the debian shipped glpsol, version 4.16 works on both
32bit
and 64bit linux systems with same sane result.
The input LP is attached, CPLEX format. Any advice welcome :)
cu
Christoph
--
-------------------------------------- Christoph Cullmann ---------
AbsInt Angewandte Informatik GmbH Email: address@hidden
Science Park 1 Tel: +49-681-38360-22
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GERMANY WWW: http://www.AbsInt.com
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Eingetragen im Handelsregister des Amtsgerichts Saarbrücken, HRB 11234
value_15318949093.lp
Description: Text document
- [Bug-glpk] Difference, 32bit build - 64bit build,
Christoph Cullmann <=