numerical.MIP: named constraints and variables, methods, structure, etc

[nathanncohen]

Hello everybody !!!

This is the last "fundamental" modification of class numerical.MIP. From now on, the methods' names should not change anymore, and the patches based upon this class should not have to be updated each time an update is sent for numerical.mip.

This patch changes mainly comports changes of structure in this class. Here is the list of what is includes :

• The line

  from sage.numerical.mip import * 
  

  has been replaced by

  from sage.numerical.mip import MixedIntegerLinearProgram
  

  as asked in clean up sage/numerical/mip.pyx #7012

• Private variables have been renamed with a '_' in front of their names. The user is not interested in them

  • x to _x
  • values to _values
  • all the variables defining the Linear Program ( variables types, bounds, name, objective, etc ) have been renamed. The new structure is easier to understand, and the code includes as a comment a Tree of these variables to explain it better.

• The __eq__ method has been added ( asked in __eq__ methods for the classes in numerical.MIP #6913 )

• Names in the Linear Program

  • Methods have been added to define names for :
    • The whole problem : set_problem_same
    • The objective function : set_objective_name
  • Methods have been modified to define names for :
    • The variables : new_variable now can take a name as part of its input
    • The constraints : similarly for add_constraint

• A function _update_variables_name. The name of variables are only computed before
  the LP is written to a file. They are obviously useless in the solving process.

• A function constraints to list the constraints of the LP.

• Function write_mps and write_lp to export the problem to MPS and LP file format ( see the docstrings for more information )

• Class MIPSolverException includes doctests of exceptions for GLPK ( CBC will follow )

• Some comments have been added to the code to ease reviews :-)

Warnings :

• To use this code you will need to have the new version of the GLPK spkg installed. It is available at ticket GLPK: named constraints and variables, export functions #7268.

Thank you for your help !!!

Nathann

Component: numerical

Author: Nathann Cohen

Reviewer: Martin Albrecht

Merged: sage-4.3.alpha1

Issue created by migration from https://trac.sagemath.org/ticket/7270

[nathanncohen]

Attachment: trac_7270.patch.gz

[malb]

comment:4

Looks good, positive review.

[mwhansen]

Author: Nathann Cohen

[mwhansen]

Reviewer: Martin Albrecht

[mwhansen]

comment:5

I had to add a missing #optional on line 550.

[mwhansen]

Merged: sage-4.3.alpha1