Opened 4 years ago

Last modified 4 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 4 years ago by

### comment:2 Changed 4 years ago by

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 4 years ago by

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

### comment:4 Changed 4 years ago by

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