Errors that can occur when solving a linear game.
"""
-class GameUnsolvableException(Exception):
+from cvxopt import matrix
+
+class GameException(Exception):
"""
- Every linear game has a solution (this follows from a general
- min-max theorem). If we can't solve the conic program associated
- with a linear game, then something is wrong with either the model of
- the input.
+ The base class for all exceptions that can occur during the solution
+ of a linear game.
"""
- def __init__(self, solution_dict):
+ def pretty_print_dict(self, solution_dict):
"""
- Create a new GameUnsolvableException object.
-
- INPUT:
-
- - ``primal`` -- the objective value of the primal cone program.
-
- - ``dual`` -- the objective value of the dual cone program.
-
- - ``solution_dict`` -- the solution dictionary returned from the cone program.
-
+ Return a pretty-printed string representation of a CVXOPT
+ solution dictionary.
"""
- tpl = 'solution failed with error: {:s}\n' \
- 'CVXOPT returned:\n{!s}'
- self.message = tpl.format(solution_dict['status'], solution_dict)
+ result = ''
+ for (k,v) in solution_dict.items():
+ if isinstance(v, matrix):
+ # Try to display vectors as rows on one line.
+ result += ' {:s}: {!s}'.format(k,v.trans())
+ else:
+ result += ' {:s}: {!s}\n'.format(k,v)
+ return result
-class GameValueMismatchException(Exception):
+
+class GameUnsolvableException(GameException):
"""
- This error occurs when the primal and dual objective value of the
- conic program associated with a linear game do not agree. By
- construction, every conic program derived from a linear game must
- have a solution and the same objective value (the "value of the
- game") is shared by both players.
-
- Each instance of this class will know the two mismatched values, and
- its ``message`` field will explain why they can't be so.
+ Every linear game has a solution (this follows from a general
+ min-max theorem). If we can't solve the conic program associated
+ with a linear game, then something is wrong with either the model of
+ the input.
"""
- def __init__(self, primal, dual, solution_dict):
+ def __init__(self, status, solution, solution_dict):
"""
- Create a new GameValueMismatchException.
+ Create a new GameUnsolvableException object.
INPUT:
- - ``primal`` -- the objective value of the primal cone program.
+ - ``status`` -- the failure status code returned by CVXOPT.
- - ``dual`` -- the objective value of the dual cone program.
+ - ``solution`` -- a Solution object.
- - ``solution_dict`` -- the solution dictionary returned from the cone program.
+ - ``solution_dict`` -- the solution dictionary returned from the
+ cone program.
"""
- tpl = 'game value mismatch for player1={:.7f}, player2={:.7f}\n' \
+ tpl = 'Solution failed with error "{:s}".\n' \
+ '{!s}\n' \
'CVXOPT returned:\n{!s}'
- self.message = tpl.format(primal, dual, solution_dict)
+ # TODO: dont convert the solution to a string, we need
+ # to output the two values as well.
+ self.message = tpl.format(status,
+ solution,
+ self.pretty_print_dict(solution_dict))