Re: [Help-glpk] glpk 4.65 release information

[Chris Matrakidis]

Hi Andrew,

In order to test the release, I tried the 2010 MIPLIB benchmark set, calling glpsol with "--pcost --cuts" and a two hour time limit. The final result is in the attached file, but the quick summary is that 20 problems from this set were solved, while there were three aborts.

Of the three aborts, problem mspp16 just run out of memory, while problems msc98-ip and ns1688347 failed in the primal simplex.

Specifically, msc98-ip failed with:

Warning: numerical instability (dual simplex, phase II)
Warning: dual simplex failed due to excessive numerical instability
Assertion failed: teta_lim >= 0.0
Error detected in file simplex/spxprim.c at line 665

while ns1688347 failed with:
Error: basis matrix is singular to working precision (cond = 3.07e+18)
Assertion failed: teta_lim >= 0.0
Error detected in file simplex/spxprim.c at line 665

Best Regards,

Chris Matrakidis

On 16 February 2018 at 11:57, Andrew Makhorin <address@hidden> wrote:

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GLPK 4.65 Release Information
*****************************

Release date: February 16, 2018

GLPK (GNU Linear Programming Kit) is intended for solving large-scale
linear programming (LP), mixed integer linear programming (MIP), and
other related problems. It is a set of routines written in ANSI C89 and
organized as a callable library.

        In this release:

        The following new API routines for LP/MIP preprocessing were
        added:

        glp_npp_alloc_wksp    allocate the preprocessor workspace
        glp_npp_load_prob     load original problem instance
        glp_npp_preprocess1   perform basic LP/MIP preprocessing
        glp_npp_build_prob    build resultant problem instance
        glp_npp_postprocess   postprocess solution to resultant problem
        glp_npp_obtain_sol    obtain solution to original problem
        glp_npp_free_wksp     free the preprocessor workspace

        See doc/npp.txt for detailed description of these API routines.

        A new, more robust implementation of locally valid simple cover
        cuts was included in the MIP solver.

        The API routine glp_init_iocp was changed to enable long-step
        option of the dual simplex by default.

See GLPK web page at <http://www.gnu.org/software/glpk/glpk.html>.

GLPK distribution can be ftp'ed from <ftp://ftp.gnu.org/gnu/glpk/> or
from some mirror ftp sites; see <http://www.gnu.org/order/ftp.html>.

MD5 check-sum is the following:

470a984a8b1c0e027bdb6d5859063fe8 *glpk-4.65.tar.gz

GLPK is also available as a Debian GNU/Linux package. See its web page
at <http://packages.debian.org/stable/math/glpk-utils>.

Precompiled GLPK binaries (lib, dll, exe) for 32- and 64-bit MS Windows
can be downloaded from <http://winglpk.sourceforge.net/>.
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