Use Click to parse command-line arguments in bimatrix.py

[nataliemes]

Changes similar to lemke.py

• Instead of using global variables, main() accepts arguments (populated by Click), which are then passed to solvers.
• Input filename is now a required argument. If the file does not exist, is not readable, or a directory is passed instead of a file, a CLI error is shown automatically.
• -h was added as a help option name.
• Options follow POSIX convention: single-character flags use a single dash, while multi-character flags use double dashes.

Other changes

Library usage:

• When using LH() as a library function, it is now mandatory to specify the labels string (it used to be empty by default).

• tracing() was replaced with 2 methods: trace_uniform_prior() with no arguments, and trace_random_priors(trace, seed=None, accuracy=1000) (where trace is the number of random priors).

  Before	Now
  game.tracing(trace=0)	game.trace_uniform_prior()
  game.tracing(trace=0, seed=1)	no longer allowed
  game.tracing(trace=20)	game.trace_random_priors(trace=20)
  game.tracing(trace=20, seed=1)	game.trace_random_priors(trace=20, seed=1)

• Instead of just returning when negative number of priors is passed to tracing(), trace_random_priors() raises a ValueError.

• To indicate that a random seed shouldn't be used in trace_random_priors(), seed is set to None (instead of a negative number like before). Negative seed values are now accepted.

CLI usage:

• --decimals and --accuracy now have range checks.

• bimatrix command is split into 2 subcommands: lh and trace.
  trace also has 2 subcommands: uniform (uses a uniform prior) and random (uses random priors, by default 1).

  Before	Now
  bimatrix (default file name was used)	no longer allowed (file name is required)
  bimatrix game_file (lh and tracing didn't run)	no longer allowed
  bimatrix game_file -LH (uses all labels)	bimatrix lh game_file
  bimatrix game_file -LH 1-2 (labels 1, 2)	bimatrix lh game_file --labels 1-2
  bimatrix game_file -LH -seed 1	no longer allowed (Lemke-Howson doesn't use a random seed)
  bimatrix game_file -trace	bimatrix trace uniform game_file
  bimatrix game_file -trace -seed 1	no longer allowed (tracing with a uniform prior doesn't use a random seed)
  bimatrix game_file -trace 1	bimatrix trace random game_file, or bimatrix trace random game_file --priors 1
  bimatrix game_file -trace 10 -seed 1	bimatrix trace random game_file --priors 10 --seed 1
  bimatrix game_file -LH -trace	no longer possible directly, since they're now separate commands

Tests:

• Tests were added for bimatrix.py.
• Correctness tests for the tracing procedure only used random priors, but now tests also use uniform priors.

[Copilot]

Pull request overview

This PR refactors bimatrix.py’s command-line interface to use Click, aligning it with the project’s other CLIs and improving argument validation and subcommand structure.

Changes:

• Replaces manual sys.argv parsing with a Click-based CLI entry point (bimatrix), including -h help alias and POSIX-style options.
• Splits the CLI into lh and trace subcommands with shared “common options” and per-subcommand options.
• Updates library entry points to accept explicit parameters (e.g., tracing(trace, seed=None, accuracy=1000)) and raises on invalid negative priors.

Comments suppressed due to low confidence (1)

src/lemke/bimatrix.py:173

• LH("") currently results in an empty label list (because rangesplit("") returns []), so the method silently finds no equilibria. Since the CLI default uses "1-" to mean “all labels”, it’s safer to treat an empty string the same way (or raise a clear error).

    def LH(self, LHstring):
        m = self.A.numrows
        n = self.A.numcolumns
        lhset = {}  # dict of equilibria and list by which label found
        labels = rangesplit(LHstring, m + n)

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[rahulsavani]

@nataliemes Could you resolve the merge conflicts please.

[rahulsavani]

Looks good to me