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RFC, ENH: Implement GAMReader and GAMWriter (#758)
* ENH: Implement GAMReader * ENH: Implement GAMWriter * DOC: Revise Examples in game_converters.py * Rename `qe_nfg_from_gam_file` to `from_gam` * Add `to_gam`
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‎quantecon/game_theory/__init__.py

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@@ -24,3 +24,4 @@
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from .logitdyn import LogitDynamics
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from .polymatrix_game import PolymatrixGame
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from .howson_lcp import polym_lcp_solver
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from .game_converters import GAMReader, GAMWriter, from_gam, to_gam

‎quantecon/game_theory/game_converters.py

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@@ -7,8 +7,11 @@
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Create a QuantEcon NormalFormGame from a gam file storing
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a 3-player Minimum Effort Game
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>>> filepath = "./tests/gam_files/minimum_effort_game.gam"
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>>> nfg = qe_nfg_from_gam_file(filepath)
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>>> import os
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>>> import quantecon.game_theory as gt
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>>> filepath = os.path.dirname(gt.__file__)
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>>> filepath += "/tests/game_files/minimum_effort_game.gam"
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>>> nfg = gt.from_gam(filepath)
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>>> print(nfg)
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3-player NormalFormGame with payoff profile array:
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[[[[ 1., 1., 1.], [ 1., 1., -9.], [ 1., 1., -19.]],
@@ -24,12 +27,183 @@
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[[-19., -19., 1.], [ -8., -8., 2.], [ 3., 3., 3.]]]]
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"""
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import numpy as np
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from .normal_form_game import Player, NormalFormGame
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from .normal_form_game import NormalFormGame
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from itertools import product
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def str2num(s):
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if '.' in s:
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return float(s)
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return int(s)
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def qe_nfg_from_gam_file(filename: str) -> NormalFormGame:
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class GAMReader:
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"""
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Reader object that converts a game in GameTracer gam format into
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a NormalFormGame.
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"""
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@classmethod
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def from_file(cls, file_path):
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"""
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Read from a gam format file.
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Parameters
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----------
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file_path : str
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Path to gam file.
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Returns
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-------
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NormalFormGame
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Examples
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--------
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Save a gam format string in a temporary file:
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>>> import tempfile
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>>> fname = tempfile.mkstemp()[1]
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>>> with open(fname, mode='w') as f:
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... f.write(\"\"\"\\
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... 2
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... 3 2
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...
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... 3 2 0 3 5 6 3 2 3 2 6 1\"\"\")
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Read the file:
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>>> g = GAMReader.from_file(fname)
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>>> print(g)
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2-player NormalFormGame with payoff profile array:
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[[[3, 3], [3, 2]],
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[[2, 2], [5, 6]],
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[[0, 3], [6, 1]]]
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"""
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with open(file_path, 'r') as f:
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string = f.read()
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return cls._parse(string)
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@classmethod
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def from_url(cls, url):
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"""
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Read from a URL.
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"""
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import urllib.request
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with urllib.request.urlopen(url) as response:
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string = response.read().decode()
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return cls._parse(string)
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@classmethod
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def from_string(cls, string):
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"""
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Read from a gam format string.
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Parameters
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----------
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string : str
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String in gam format.
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Returns
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-------
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NormalFormGame
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Examples
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--------
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>>> string = \"\"\"\\
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... 2
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... 3 2
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...
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... 3 2 0 3 5 6 3 2 3 2 6 1\"\"\"
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>>> g = GAMReader.from_string(string)
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>>> print(g)
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2-player NormalFormGame with payoff profile array:
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[[[3, 3], [3, 2]],
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[[2, 2], [5, 6]],
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[[0, 3], [6, 1]]]
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"""
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return cls._parse(string)
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@staticmethod
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def _parse(string):
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tokens = string.split()
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N = int(tokens.pop(0))
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nums_actions = tuple(int(tokens.pop(0)) for _ in range(N))
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payoffs = np.array([str2num(s) for s in tokens])
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na = np.prod(nums_actions)
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payoffs2d = payoffs.reshape(N, na)
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players = [
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Player(
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payoffs2d[i, :].reshape(nums_actions, order='F').transpose(
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list(range(i, N)) + list(range(i))
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)
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) for i in range(N)
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]
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return NormalFormGame(players)
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class GAMWriter:
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"""
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Writer object that converts a NormalFormgame into a game in
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GameTracer gam format.
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"""
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@classmethod
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def to_file(cls, g, file_path):
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"""
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Save the GameTracer gam format string representation of the
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NormalFormGame `g` to a file.
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Parameters
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----------
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g : NormalFormGame
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file_path : str
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Path to the file to write to.
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"""
170+
with open(file_path, 'w') as f:
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f.write(cls._dump(g) + '\n')
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@classmethod
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def to_string(cls, g):
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"""
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Return a GameTracer gam format string representing the
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NormalFormGame `g`.
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Parameters
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----------
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g : NormalFormGame
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Returns
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-------
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str
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String representation in gam format.
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"""
189+
return cls._dump(g)
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@staticmethod
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def _dump(g):
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s = str(g.N) + '\n'
194+
s += ' '.join(map(str, g.nums_actions)) + '\n\n'
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for i, player in enumerate(g.players):
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payoffs = np.array2string(
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player.payoff_array.transpose(
199+
list(range(g.N-i, g.N)) + list(range(g.N-i))
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).ravel(order='F'))[1:-1]
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s += ' '.join(payoffs.split()) + ' '
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return s.rstrip()
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def from_gam(filename: str) -> NormalFormGame:
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"""
34208
Makes a QuantEcon Normal Form Game from a gam file.
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@@ -51,32 +225,22 @@ def qe_nfg_from_gam_file(filename: str) -> NormalFormGame:
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http://dags.stanford.edu/Games/gametracer.html
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"""
54-
with open(filename, 'r') as file:
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lines = file.readlines()
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combined = [
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token
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for line in lines
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for token in line.split()
60-
]
228+
return GAMReader.from_file(filename)
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62-
i = iter(combined)
63-
players = int(next(i))
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actions = [int(next(i)) for _ in range(players)]
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66-
nfg = NormalFormGame(actions)
231+
def to_gam(g, file_path=None):
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"""
233+
Write a NormalFormGame to a file in gam format.
67234
68-
entries = [
69-
{
70-
tuple(reversed(action_combination)): float(next(i))
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for action_combination in product(
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*[range(a) for a in actions])
73-
}
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for _ in range(players)
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]
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Parameters
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----------
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g : NormalFormGame
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77-
for action_combination in product(*[range(a) for a in actions]):
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nfg[action_combination] = tuple(
79-
entries[p][action_combination] for p in range(players)
80-
)
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file_path : str, optional(default=None)
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Path to the file to write to. If None, the result is returned as
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a string.
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return nfg
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"""
244+
if file_path is None:
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return GAMWriter.to_string(g)
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return GAMWriter.to_file(g, file_path)

‎quantecon/game_theory/tests/test_game_converters.py

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@@ -0,0 +1,61 @@
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"""
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Tests for game_theory/game_converters.py
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"""
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import os
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from tempfile import NamedTemporaryFile
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from numpy.testing import assert_string_equal
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from quantecon.game_theory import NormalFormGame, GAMWriter, to_gam
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10+
11+
class TestGAMWriter:
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def setup_method(self):
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nums_actions = (2, 2, 2)
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g = NormalFormGame(nums_actions)
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g[0, 0, 0] = (0, 8, 16)
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g[1, 0, 0] = (1, 9, 17)
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g[0, 1, 0] = (2, 10, 18)
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g[1, 1, 0] = (3, 11, 19)
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g[0, 0, 1] = (4, 12, 20)
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g[1, 0, 1] = (5, 13, 21)
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g[0, 1, 1] = (6, 14, 22)
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g[1, 1, 1] = (7, 15, 23)
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self.g = g
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self.s_desired = """\
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3
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2 2 2
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0. 1. 2. 3. 4. 5. 6. 7. \
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8. 9. 10. 11. 12. 13. 14. 15. \
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16. 17. 18. 19. 20. 21. 22. 23."""
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33+
def test_to_file(self):
34+
with NamedTemporaryFile(delete=False) as tmp_file:
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temp_path = tmp_file.name
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GAMWriter.to_file(self.g, temp_path)
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38+
with open(temp_path, 'r') as f:
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s_actual = f.read()
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assert_string_equal(s_actual, self.s_desired + '\n')
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42+
os.remove(temp_path)
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def test_to_string(self):
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s_actual = GAMWriter.to_string(self.g)
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assert_string_equal(s_actual, self.s_desired)
48+
49+
def test_to_gam(self):
50+
s_actual = to_gam(self.g)
51+
assert_string_equal(s_actual, self.s_desired)
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53+
with NamedTemporaryFile(delete=False) as tmp_file:
54+
temp_path = tmp_file.name
55+
to_gam(self.g, temp_path)
56+
57+
with open(temp_path, 'r') as f:
58+
s_actual = f.read()
59+
assert_string_equal(s_actual, self.s_desired + '\n')
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61+
os.remove(temp_path)

‎quantecon/game_theory/tests/test_howson_lcp.py

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@@ -4,7 +4,7 @@
44

55
import numpy as np
66
from numpy.testing import assert_, assert_allclose
7-
from quantecon.game_theory.game_converters import qe_nfg_from_gam_file
7+
from quantecon.game_theory.game_converters import from_gam
88
from quantecon.game_theory import (
99
Player,
1010
NormalFormGame,
@@ -22,7 +22,7 @@
2222

2323
def test_polym_lcp_solver_where_solution_is_pure_NE():
2424
filename = "big_polym.gam"
25-
nfg = qe_nfg_from_gam_file(os.path.join(data_dir, filename))
25+
nfg = from_gam(os.path.join(data_dir, filename))
2626
polymg = PolymatrixGame.from_nf(nfg)
2727
ne = polym_lcp_solver(polymg)
2828
worked = nfg.is_nash(ne)
@@ -31,7 +31,7 @@ def test_polym_lcp_solver_where_solution_is_pure_NE():
3131

3232
def test_polym_lcp_solver_where_lcp_solver_must_backtrack():
3333
filename = "triggers_back_case.gam"
34-
nfg = qe_nfg_from_gam_file(os.path.join(data_dir, filename))
34+
nfg = from_gam(os.path.join(data_dir, filename))
3535
polymg = PolymatrixGame.from_nf(nfg)
3636
ne = polym_lcp_solver(polymg)
3737
worked = nfg.is_nash(ne)
@@ -305,7 +305,7 @@ def test_solves_multiplayer_rps_like():
305305

306306
def test_different_starting():
307307
filename = "triggers_back_case.gam"
308-
nfg = qe_nfg_from_gam_file(os.path.join(data_dir, filename))
308+
nfg = from_gam(os.path.join(data_dir, filename))
309309
polymg = PolymatrixGame.from_nf(nfg)
310310
starting = [3, 2, 2, 0, 3]
311311
# We also notice that changing the start

‎quantecon/game_theory/tests/test_polymatrix_game.py

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"""
44

55
from numpy.testing import assert_, assert_raises
6-
from quantecon.game_theory.game_converters import qe_nfg_from_gam_file
6+
from quantecon.game_theory.game_converters import from_gam
77
from quantecon.game_theory import NormalFormGame, PolymatrixGame
88
from numpy import allclose, zeros
99

@@ -39,13 +39,13 @@ class TestPolymatrixGame():
3939
@classmethod
4040
def setup_class(cls):
4141
filename = "minimum_effort_game.gam"
42-
cls.non_pmg = qe_nfg_from_gam_file(
42+
cls.non_pmg = from_gam(
4343
os.path.join(data_dir, filename))
4444
filename = "big_polym.gam"
45-
cls.pmg1 = qe_nfg_from_gam_file(
45+
cls.pmg1 = from_gam(
4646
os.path.join(data_dir, filename))
4747
filename = "triggers_back_case.gam"
48-
cls.pmg2 = qe_nfg_from_gam_file(
48+
cls.pmg2 = from_gam(
4949
os.path.join(data_dir, filename))
5050
bimatrix = [[(54, 23), (72, 34)],
5151
[(92, 32), (34, 36)],

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