#19523: Adding constraints for the wrong MILP crashes Sage
--------------------------------------+-------------------------
Reporter: jdemeyer | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.10
Component: linear programming | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: #19525, #20360 | Stopgaps:
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Changes (by mkoeppe):
* dependencies: #19525 => #19525, #20360
Old description:
> {{{
> sage: p = MixedIntegerLinearProgram(solver="glpk")
> sage: q = MixedIntegerLinearProgram(solver="glpk")
> sage: q.add_constraint(p[0] <= 1)
> ------------------------------------------------------------------------
> Unhandled SIGABRT: An abort() occurred in Sage.
> This probably occurred because a *compiled* component of Sage has a bug
> in it and is not properly wrapped with sig_on(), sig_off().
> Sage will now terminate.
> ------------------------------------------------------------------------
> }}}
>
> With #19525, this improves to not crashing Sage:
> {{{
> sage: sage: p = MixedIntegerLinearProgram(solver="glpk")
> sage: sage: q = MixedIntegerLinearProgram(solver="glpk")
> sage: sage: q.add_constraint(p[0] <= 1)
> ---------------------------------------------------------------------------
> GLPKError Traceback (most recent call
> last)
> ...
> GLPKError: glp_set_mat_row: i = 1; len = 1; invalid row length
> Error detected in file glpapi01.c at line 760
> }}}
> This ticket is to actually fix the error completely or give a better
> error message.
>
> Also a crash with the COIN backend.
>
> And low-level error message with the PPL and InteractiveLP (#20296 )
> backends.
>
> The CVX backend silently adds a new variable that is accessible only to
> the backend:.
> {{{
> sage: sage: default_mip_solver("cvxopt")
> sage: sage: p = MixedIntegerLinearProgram()
> sage: sage: q = MixedIntegerLinearProgram()
> sage: sage: q.add_constraint(p[0] <= 1)
> sage: q.number_of_variables()
> 1
> }}}
New description:
{{{
sage: p = MixedIntegerLinearProgram(solver="glpk")
sage: q = MixedIntegerLinearProgram(solver="glpk")
sage: q.add_constraint(p[0] <= 1)
------------------------------------------------------------------------
Unhandled SIGABRT: An abort() occurred in Sage.
This probably occurred because a *compiled* component of Sage has a bug
in it and is not properly wrapped with sig_on(), sig_off().
Sage will now terminate.
------------------------------------------------------------------------
}}}
With #19525, this improves to not crashing Sage:
{{{
sage: sage: p = MixedIntegerLinearProgram(solver="glpk")
sage: sage: q = MixedIntegerLinearProgram(solver="glpk")
sage: sage: q.add_constraint(p[0] <= 1)
---------------------------------------------------------------------------
GLPKError Traceback (most recent call
last)
...
GLPKError: glp_set_mat_row: i = 1; len = 1; invalid row length
Error detected in file glpapi01.c at line 760
}}}
This ticket is to actually fix the error completely or give a better error
message.
Also a crash with the COIN backend (#20360).
And low-level error message with the PPL and InteractiveLP (#20296 )
backends.
The CVX backend silently adds a new variable that is accessible only to
the backend:.
{{{
sage: sage: default_mip_solver("cvxopt")
sage: sage: p = MixedIntegerLinearProgram()
sage: sage: q = MixedIntegerLinearProgram()
sage: sage: q.add_constraint(p[0] <= 1)
sage: q.number_of_variables()
1
}}}
--
--
Ticket URL: <http://trac.sagemath.org/ticket/19523#comment:12>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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