From 8cc672bead56843f9d67b3ac21acbee4a4af2e54 Mon Sep 17 00:00:00 2001
From: Vivien Maisonneuve <v.maisonneuve@gmail.com>
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