From 8cc672bead56843f9d67b3ac21acbee4a4af2e54 Mon Sep 17 00:00:00 2001 From: Vivien Maisonneuve Date: Mon, 30 Jun 2014 11:55:28 +0200 Subject: [PATCH] Use OrderedDict to store Expression coefficients --- pypol/linexprs.py | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/pypol/linexprs.py b/pypol/linexprs.py index 9ab5c86..d8b020d 100644 --- a/pypol/linexprs.py +++ b/pypol/linexprs.py @@ -3,6 +3,7 @@ import functools import numbers import re +from collections import OrderedDict from fractions import Fraction, gcd @@ -67,13 +68,14 @@ class Expression: raise TypeError('coefficients must be rational numbers ' 'or Constant instances') self._coefficients[symbol] = coefficient + self._coefficients = OrderedDict(sorted(self._coefficients.items())) if isinstance(constant, Constant): constant = constant.constant if not isinstance(constant, numbers.Rational): raise TypeError('constant must be a rational number ' 'or a Constant instance') self._constant = constant - self._symbols = tuple(sorted(self._coefficients)) + self._symbols = tuple(self._coefficients) self._dimension = len(self._symbols) return self @@ -90,8 +92,7 @@ class Expression: __getitem__ = coefficient def coefficients(self): - for symbol in self.symbols: - yield symbol, self.coefficient(symbol) + yield from self._coefficients.items() @property def constant(self): @@ -220,7 +221,7 @@ class Expression: return Gt(self, other) def __hash__(self): - return hash((tuple(sorted(self._coefficients.items())), self._constant)) + return hash((tuple(self.coefficients()), self._constant)) def _toint(self): lcm = functools.reduce(lambda a, b: a*b // gcd(a, b), -- 2.20.1