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PPL mip solver runs out of memory for trivial 3-variable IP #24146

Open mkoeppe opened 7 years ago

mkoeppe commented 7 years ago 
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()

CC: @yuan-zhou @dimpase @jdemeyer

Component: numerical

Issue created by migration from https://trac.sagemath.org/ticket/24146

dimpase commented 7 years ago
comment:1

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

mkoeppe commented 7 years ago
comment:2

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.

dimpase commented 7 years ago
comment:3

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

tscrim commented 6 years ago
comment:4

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.