Allow xor clause in DIMACS files (format extended by cryptominisat)

[sagetrac-tmonteil]

Cryptominisat accepts xor clauses but is currently not able to read DIMACS files with such clauses, see this ask question.

Since some other solvers might accept xor clauses, the parsing of such clauses is done on the generic solver.

Component: linear programming

Author: Thierry Monteil

Branch/Commit: 4b3cc1b

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/26329

[sagetrac-tmonteil]

Branch: u/tmonteil/allow_xor_clause_in_dimacs_files__format_extended_by_cryptominisat_

[sagetrac-tmonteil]

Commit: 6712e18

[sagetrac-tmonteil]

New commits:

6712e18

#26329 : SatSolver.read can parse xor clauses

[tscrim]

comment:3

Could you add a test showing the error is correctly raised? Should the file also be closed when the error message is raised?

Also a little nitpick, but error messages (following Python conventions) do not start with a capital letter.

[tscrim]

Reviewer: Travis Scrimshaw

[sagetrac-git]

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

4b3cc1b

#26329 : reviewer's comments

[sagetrac-git]

Changed commit from 6712e18 to 4b3cc1b

[sagetrac-tmonteil]

comment:5

Done.

Note that i used SatLP to test the error message, but in #26330 i plan to let SatLP accept xor clauses, so hopefully #26334 and #26335 will be accepted before so that i can use PicoSAT (which does not accept xor clauses) instead.

[tscrim]

comment:6

Thanks. I will review #26334 and #26335 now.

[vbraun]

Changed branch from u/tmonteil/allow_xor_clause_in_dimacs_files__format_extended_by_cryptominisat_ to 4b3cc1b