Hi,
While trying to solve attached ILP problem as below:
int
main(void)
{
glp_prob *lp;
lp = glp_create_prob();
assert(!glp_read_lp(lp, NULL, repl-ilp-xXNtiz));
assert(!glp_simplex(lp, NULL) glp_get_status(lp) == GLP_OPT);
lpx_set_int_parm(lp, LPX_K_USECUTS, LPX_C_ALL);
lpx_set_real_parm(lp, LPX_K_TMLIM, 1);
lpx_adv_basis(lp);
{
int ret = lpx_intopt(lp);
assert(ret == LPX_E_OK || ret == LPX_E_TMLIM);
}
return 0;
}
The final assertion fails with ret set to 211 (LPX_E_SING). Below is
the program output:
glp_read_lp: reading problem data from `repl-ilp-xXNtiz'...
glp_read_lp: 101 rows, 166 columns, 531 non-zeros
glp_read_lp: 166 integer columns, all of which are binary
glp_read_lp: 272 lines were read
* 0: objval = 0.0e+00 infeas = 0.0e+00 (0)
* 124: objval = 3.702857143e+01 infeas = 8.881784197e-16 (0)
OPTIMAL SOLUTION FOUND
lpx_adv_basis: size of triangular part = 101
ipp_basic_tech: 0 row(s) and 0 column(s) removed
ipp_reduce_bnds: 1 pass(es) made, 0 bound(s) reduced
ipp_basic_tech: 0 row(s) and 0 column(s) removed
ipp_reduce_coef: 1 pass(es) made, 0 coefficient(s) reduced
lpx_intopt: presolved MIP has 101 rows, 166 columns, 531 non-zeros
lpx_intopt: 166 integer columns, all of which are binary
lpx_adv_basis: size of triangular part = 101
Solving LP relaxation...
* 124: objval = 0.0e+00 infeas = 0.0e+00 (0)
* 134: objval = 3.702857143e+01 infeas = 0.0e+00 (0)
OPTIMAL SOLUTION FOUND
Creating the conflict graph...
The conflict graph has 2*166 vertices and 535 edges
Generating cutting planes...
134: obj = 3.702857143e+01 frac =33 cuts = 0 (0)
331: obj = 2.8e+01 frac =18 cuts =81 (162)
81 mixed cover cut(s) added
Integer optimization begins...
+ 331: mip = not found yet = +inf(1; 0)
Gomory's cuts enabled
MIR cuts enabled
+ 394:2.7e+01 = 2.8e+01 3.7% (4; 0)
spx_invert: the basis matrix is singular
spx_simplex: numerical problems with basis matrix
spx_simplex: sorry, basis recovery procedure not implemented yet
ios_driver: unable to solve current LP relaxation; glp_simplex returned 5
+ 1719: mip = 2.7e+01 = 2.8e+01 3.7% (83; 31)
glp_intopt: cannot solve current LP relaxation
repl-k: src/ilp.c:153: solve_ilp: Assertion `ret == 200' failed.
The strange thing is, while above codes works perfectly on my notebook
(32bit), it fails to run on a remote server (64bit). Below are system
specifications of both machines.
REMOTE-SERVER
-
$ gcc -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.3.2-1.1'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3
--program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --enable-mpfr --enable-cld --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.3.2 (Debian 4.3.2-1.1)
$ glpsol -v
GLPSOL: GLPK LP/MIP Solver 4.29
NOTEBOOK
$ gcc -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.3.2-1.1'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3
--program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --enable-mpfr --enable-targets=all --enable-cld
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
gcc version 4.3.2 (Debian 4.3.2-1.1)
You have new mail in /var/mail/vy
$ glpsol -v
GLPSOL: GLPK LP/MIP Solver 4.29
What might I be missing? Any ideas?
Regards.
repl-ilp-xXNtiz
Description: Binary data
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