Changes between Initial Version and Version 2 of Ticket #18733


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Timestamp:
06/20/15 06:55:59 (6 years ago)
Author:
dimpase
Comment:

Note that not all Sage's LP solvers use a simplex method. E.g. cvxopt does not. In this case is makes no sense talking about tableaux...

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  • Ticket #18733

    • Property Type changed from PLEASE CHANGE to enhancement

  • Ticket #18733 – Description

    initial v2  
    1 If one uses Sage's MixedIntegerLinearProgram class for solving an LP, it is useful to access dictionary (tableau) data corresponding to the current (often optimal) basis. For example, one needs this to compute tableau cutting planes such as Gomory's fractional cut.
     1If one uses Sage's `MixedIntegerLinearProgram` class for solving an LP, it is useful to access dictionary (tableau) data corresponding to the current (often optimal) basis. For example, one needs this to compute tableau cutting planes such as Gomory's fractional cut.
    22
    33The Sage interface should, of course, be designed to work consistently across all solvers. There are some subtleties here. Best to be compatible with a library that has already sorted most of it out: In the COIN open solver interface, there are the functions [https://projects.coin-or.org/Osi/browser/trunk/Osi/src/Osi/OsiSolverInterface.hpp#L1860 getBInvARow], getBInvRow, getBInvACol, getBInvCol.