LPAbstractDictionary: Refactor leaving_coefficients, entering_coefficients using new methods row_coefficients, column_coefficients

[mkoeppe]

This is preparation for the cutting plane method (#18805 ), which needs to read out a row of the dictionary.
(Seems cleaner than having to do "leave(i), get leaving_coefficients(), leave(None)".)

The patch is also adding @abstract_method stubs for the methods that the concrete dictionaries need to implement.

CC: @novoselt

Component: numerical

Author: Peijun Xiao, Matthias Koeppe

Branch/Commit: a382ec1

Reviewer: Andrey Novoseltsev

Issue created by migration from https://trac.sagemath.org/ticket/20500

[mkoeppe]

Branch: u/mkoeppe/lpabstractdictionary__refactor_leaving_coefficients__entering_coefficients_using_new_methods_row_coefficients__column_coefficients

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1 +1,2 @@
-
+This is preparation for the cutting plane method (#18805 ), which needs to read out a row of the dictionary.
+(Seems cleaner than having to do "leave(i), get leaving_coefficients(), leave(None)".)

[mkoeppe]

Author: Peijun Xiao, Matthias Koeppe

[mkoeppe]

New commits:

d6ee048

Refactor leaving_coefficients in terms of new method row_coefficients

[mkoeppe]

Commit: d6ee048

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

3cbdeef	Fixup
db52d0e	Add @abstract_method methods to LPAbstractDictionary
4e9955e	Refactor entering_coefficients in terms of new method column_coefficients

[sagetrac-git]

Changed commit from d6ee048 to 4e9955e

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,2 +1,4 @@
 This is preparation for the cutting plane method (#18805 ), which needs to read out a row of the dictionary.
 (Seems cleaner than having to do "leave(i), get leaving_coefficients(), leave(None)".)
+
+The patch is also adding `@`abstract_method stubs for the methods that the concrete dictionaries need to implement.

[novoselt]

Reviewer: Andrey Novoseltsev

[novoselt]

comment:5

I am not convinced there is much point in abstract methods, which leads to duplication of examples and tests, but in any way:

• leaving_coefficients has wrong documentation
• column_coefficients has wrong documentation twice

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

a382ec1

Fix documentation

[sagetrac-git]

Changed commit from 4e9955e to a382ec1

[mkoeppe]

comment:8

Replying to @novoselt:

I am not convinced there is much point in abstract methods, which leads to duplication of examples and tests,

I think it's quite nice in combination with _test_not_implemented_methods and as a documentation of the interface.

but in any way:

• leaving_coefficients has wrong documentation
• column_coefficients has wrong documentation twice

Fixed.