Opened 3 years ago

Last modified 3 years ago

#24146 new defect

PPL mip solver runs out of memory for trivial 3-variable IP

Reported by: mkoeppe Owned by:
Priority: major Milestone: sage-8.1
Component: numerical Keywords:
Cc: yzh, dimpase, jdemeyer Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description 

sage: ip = MixedIntegerLinearProgram(maximization=True, solver='ppl')
sage: x = ip.new_variable(integer=True)
sage: ip.set_objective(-4*x[0]) 
sage: ip.add_constraint(-2*x[0] + x[1] <= -2)
sage: ip.add_constraint(-12*x[0] + x[2] <= -12)
sage: ip.add_constraint(-8*x[0] - 2*x[1] - x[2] <= -11)
sage: ip.solve()

Change History (4)

comment:1 Changed 3 years ago by dimpase

ppl does not do integer LPs, if I recall right.

comment:2 Changed 3 years ago by mkoeppe

Is this the real Dima?

Ppl does have a MIP solver. Some time back I added the missing parts to the Sage ppl interface. Your recollection is probably based on the state of things before that.

comment:3 Changed 3 years ago by dimpase

Right. That's me, as you can see from a characteristic memory lapse. :-)

comment:4 Changed 3 years ago by tscrim

It is also bad that this is not interruptible, but that is a separate issue. However, isn't this a problem with upstream (i.e. PPL) rather than Sage? At least, using the GLPK solver, I get -8.0.

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