LPCleanDictionary - floating-point helper class for interactive simplex method

[mkoeppe]

This module provides a "clean" dictionary view on a dictionary with
floating-point numbers. Cleaning means to change almost-zeros to exact
zeros, allowing the Interactive Simplex Method to recognize primal and
dual feasibility and to avoid pivoting on zero pivot elements.

(Split out from the larger ticket #18804.)

Depends on #20874

CC: @uduse @pgxiao

Component: numerical

Author: Aedi Wang

Branch/Commit: u/mkoeppe/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method @ ae348f7

Reviewer: Michael Orlitzky

Issue created by migration from https://trac.sagemath.org/ticket/20203

[mkoeppe]

Branch: u/mkoeppe/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method

[mkoeppe]

Commit: 24eaba3

[mkoeppe]

comment:2

To be done:

• Tests should be based on normal dictionaries, not the backend dictionaries from LPBackendDictionary - a debugging view of a MIP backend connected to interactive_simplex_method #18804
• Perhaps have InteractiveLPProblem use LPCleanDictionary automatically when field is inexact

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New commits:

24eaba3

clean_dictionary.py copied from f45615c

[sagetrac-git]

Changed commit from 24eaba3 to 067b75d

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

067b75d

clean_dictionary.py copied from f45615c

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

2e4496b

clean_dictionary.py copied from f45615c

[sagetrac-git]

Changed commit from 067b75d to 2e4496b

[uduse]

Changed branch from u/mkoeppe/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method to u/zwang/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method

[mkoeppe]

Dependencies: #20874

[mkoeppe]

New commits:

6cad314	add objective_name() to dictionary interface
288e6f7	Doc fix
62b9ec6	clean_dictionary.py copied from f45615c
7bdddd4	revise doc tests and implementation to use LPDictionary

[mkoeppe]

Changed commit from 2e4496b to 7bdddd4

[mkoeppe]

Changed branch from u/zwang/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method to u/mkoeppe/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method

[mkoeppe]

comment:8

Needs more work. The interface has changed and it is now necessary to implement methods row_coefficients, column_coefficients instead of leaving_coefficients, entering_coefficients. Also need to use these new methods in the dictionary() method. And it needs an __eq__ method.

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New commits:

65aafcd	Merge remote-tracking branch 'trac/u/zwang/lpcleandictionary___floating_point_helper_class_for_interactive_simplex_method' into test_20203
259bf2f	LPCleanDictionary: Run the testsuite
5cfc380	LPCleanDictionary: Implement row_coefficients instead of leaving_coefficients

[mkoeppe]

Changed commit from 7bdddd4 to 5cfc380

[sagetrac-git]

Changed commit from 5cfc380 to ae348f7