Improve GLPK error handling

[jdemeyer]

This ticket adds a proper error handler for GLPK (similar to what we already have for PARI, NTL, ...). It suffices to add sig_on()/sig_off() around a GLPK call to get an error message.

Some more cleanup is also done:

1. change the implementation of MIPSolverException to just inherit from RuntimeError without any custom implementation.
2. use MemoryAllocator in a few places to make some allocations safer.

This branch requires a patch to GLPK, a modified version of it was accepted upstream: http://lists.gnu.org/archive/html/help-glpk/2015-11/msg00008.html

Upstream: Fixed upstream, in a later stable release.

CC: @nathanncohen

Component: cython

Author: Jeroen Demeyer

Branch/Commit: 76a11fd

Reviewer: Vincent Delecroix

Issue created by migration from https://trac.sagemath.org/ticket/19525

[jdemeyer]

Dependencies: #19527

[jdemeyer]

Branch: u/jdemeyer/improve_glpk_error_handling

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

f808061

Implement GLPK error handling

[sagetrac-git]

Commit: f808061

[jdemeyer]

Upstream: Reported upstream. No feedback yet.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

f312818

Improve printing of solver exceptions

[sagetrac-git]

Changed commit from f808061 to f312818

[jdemeyer]

Changed upstream from Reported upstream. No feedback yet. to Reported upstream. Developers acknowledge bug.

[sagetrac-git]

Changed commit from f312818 to 18265ee

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

18265ee

Rename glp_have_error -> glp_at_error

[jdemeyer]

Changed upstream from Reported upstream. Developers acknowledge bug. to Fixed upstream, but not in a stable release.

[jdemeyer]

Changed upstream from Fixed upstream, but not in a stable release. to Fixed upstream, in a later stable release.

[jdemeyer]

Changed upstream from Fixed upstream, in a later stable release. to Not yet reported upstream; Will do shortly.

[jdemeyer]

comment:14

Upstream claims we are mis-using the GLPK error hook. They are probably right. However, given that I'd like to keep "upgrade GLPK" separated from this ticket, I still propose to review this ticket as-is and then deal with the upgrade on a new ticket.

[jdemeyer]

Changed upstream from Not yet reported upstream; Will do shortly. to Fixed upstream, in a later stable release.

[dimpase]

comment:15

Does a reviewer need to create a patched GLPK tarball himself?

[jdemeyer]

comment:16

Replying to @dimpase:

Does a reviewer need to create a patched GLPK tarball himself?

No. This isn't a GLPK upgrade.

[mkoeppe]

comment:18

Any news on the upstream situation?

[videlec]

comment:19

does not apply on the latest beta

[sagetrac-git]

Changed commit from 5211376 to 3e33342

[videlec]

Changed branch from u/jdemeyer/improve_glpk_error_handling to u/vdelecroix/19525

[videlec]

Changed commit from 3e33342 to 71f52a4

[videlec]

comment:29

A commit to fix changes in error messages.

---

New commits:

71f52a4

Trac 19525: fix error messages for cplex and gurobi

[mkoeppe]

comment:30

See also #10232

[videlec]

comment:31

Indeed, in order to fix #10232 there need to be the appropriate sig_on and sig_off around the GLPK calls.

[videlec]

comment:32

Jeroen, do you prefer another ticket to add the appropriate sig_on/sig_off around GLPK calls?

[videlec]

comment:33

If yes, then the ticket is good to go from my point of view.

[jdemeyer]

Reviewer: Vincent Delecroix

[vbraun]

comment:35

Fails on 32-bit

sage -t --long src/sage/numerical/backends/glpk_backend.pyx
**********************************************************************
File "src/sage/numerical/backends/glpk_backend.pyx", line 847, in sage.numerical.backends.glpk_backend.GLPKBackend.solve
Failed example:
    lp.solve()
Expected:
    Traceback (most recent call last):
    ...
    GLPKError: Assertion failed: col->lb < col->ub
    Error detected in file glpnpp05.c at line ...
Got:
    <BLANKLINE>
    Traceback (most recent call last):
      File "/home/buildbot/slave/sage_git/build/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 496, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/home/buildbot/slave/sage_git/build/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 858, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.numerical.backends.glpk_backend.GLPKBackend.solve[24]>", line 1, in <module>
        lp.solve()
      File "sage/numerical/mip.pyx", line 2115, in sage.numerical.mip.MixedIntegerLinearProgram.solve (/home/buildbot/slave/sage_git/build/src/build/cythonized/sage/numerical/mip.c:14757)
        self._backend.solve()
      File "sage/numerical/backends/glpk_backend.pyx", line 1005, in sage.numerical.backends.glpk_backend.GLPKBackend.solve (/home/buildbot/slave/sage_git/build/src/build/cythonized/sage/numerical/backends/glpk_backend.cpp:8406)
        sig_on()
    GLPKError: Assertion failed: q->lb < q->ub
    Error detected in file glpnpp03.c at line 557
**********************************************************************
1 item had failures:
   1 of  76 in sage.numerical.backends.glpk_backend.GLPKBackend.solve

[jdemeyer]

Changed branch from u/vdelecroix/19525 to u/jdemeyer/19525

[jdemeyer]

comment:37

This should do the trick...

---

New commits:

76a11fd

Use ellipsis in assertion error message

[jdemeyer]

Changed commit from 71f52a4 to 76a11fd

[vbraun]

Changed branch from u/jdemeyer/19525 to 76a11fd