X-Git-Url: https://svn.cri.ensmp.fr/git/linpy.git/blobdiff_plain/5b661514c1bbabd8205fdbd22a0ba0f6b1ac6305..9de08f6d690b0ad9f279e9ff78646c307b6beb7e:/pypol/linexprs.py?ds=inline diff --git a/pypol/linexprs.py b/pypol/linexprs.py index c8745b5..c5f4336 100644 --- a/pypol/linexprs.py +++ b/pypol/linexprs.py @@ -40,26 +40,26 @@ class Expression: return Rational(constant) if isinstance(coefficients, Mapping): coefficients = coefficients.items() + coefficients = list(coefficients) for symbol, coefficient in coefficients: if not isinstance(symbol, Symbol): raise TypeError('symbols must be Symbol instances') if not isinstance(coefficient, numbers.Rational): raise TypeError('coefficients must be rational numbers') - coefficients = [(symbol, Fraction(coefficient)) - for symbol, coefficient in coefficients if coefficient != 0] if not isinstance(constant, numbers.Rational): raise TypeError('constant must be a rational number') - constant = Fraction(constant) if len(coefficients) == 0: return Rational(constant) if len(coefficients) == 1 and constant == 0: symbol, coefficient = coefficients[0] if coefficient == 1: return symbol + coefficients = [(symbol, Fraction(coefficient)) + for symbol, coefficient in coefficients if coefficient != 0] + coefficients.sort(key=lambda item: item[0].sortkey()) self = object().__new__(cls) - self._coefficients = OrderedDict(sorted(coefficients, - key=lambda item: item[0].sortkey())) - self._constant = constant + self._coefficients = OrderedDict(coefficients) + self._constant = Fraction(constant) self._symbols = tuple(self._coefficients) self._dimension = len(self._symbols) return self @@ -67,10 +67,7 @@ class Expression: def coefficient(self, symbol): if not isinstance(symbol, Symbol): raise TypeError('symbol must be a Symbol instance') - try: - return Rational(self._coefficients[symbol]) - except KeyError: - return Rational(0) + return Rational(self._coefficients.get(symbol, 0)) __getitem__ = coefficient @@ -131,49 +128,48 @@ class Expression: constant = self._constant - other._constant return Expression(coefficients, constant) + @_polymorphic def __rsub__(self, other): - return -(self - other) + return other - self - @_polymorphic def __mul__(self, other): - if isinstance(other, Rational): - return other.__rmul__(self) + if isinstance(other, numbers.Rational): + coefficients = ((symbol, coefficient * other) + for symbol, coefficient in self._coefficients.items()) + constant = self._constant * other + return Expression(coefficients, constant) return NotImplemented __rmul__ = __mul__ - @_polymorphic def __truediv__(self, other): - if isinstance(other, Rational): - return other.__rtruediv__(self) + if isinstance(other, numbers.Rational): + coefficients = ((symbol, coefficient / other) + for symbol, coefficient in self._coefficients.items()) + constant = self._constant / other + return Expression(coefficients, constant) return NotImplemented - __rtruediv__ = __truediv__ - @_polymorphic def __eq__(self, other): - # "normal" equality + # returns a boolean, not a constraint # see http://docs.sympy.org/dev/tutorial/gotchas.html#equals-signs return isinstance(other, Expression) and \ self._coefficients == other._coefficients and \ self._constant == other._constant - @_polymorphic def __le__(self, other): from .polyhedra import Le return Le(self, other) - @_polymorphic def __lt__(self, other): from .polyhedra import Lt return Lt(self, other) - @_polymorphic def __ge__(self, other): from .polyhedra import Ge return Ge(self, other) - @_polymorphic def __gt__(self, other): from .polyhedra import Gt return Gt(self, other) @@ -324,8 +320,8 @@ class Symbol(Expression): raise TypeError('name must be a string') self = object().__new__(cls) self._name = name.strip() - self._coefficients = {self: 1} - self._constant = 0 + self._coefficients = {self: Fraction(1)} + self._constant = Fraction(0) self._symbols = (self,) self._dimension = 1 return self @@ -344,8 +340,7 @@ class Symbol(Expression): return True def __eq__(self, other): - return not isinstance(other, Dummy) and isinstance(other, Symbol) \ - and self.name == other.name + return self.sortkey() == other.sortkey() def asdummy(self): return Dummy(self.name) @@ -369,8 +364,10 @@ class Symbol(Expression): @classmethod def fromsympy(cls, expr): import sympy - if isinstance(expr, sympy.Symbol): - return cls(expr.name) + if isinstance(expr, sympy.Dummy): + return Dummy(expr.name) + elif isinstance(expr, sympy.Symbol): + return Symbol(expr.name) else: raise TypeError('expr must be a sympy.Symbol instance') @@ -382,11 +379,13 @@ class Dummy(Symbol): def __new__(cls, name=None): if name is None: name = 'Dummy_{}'.format(Dummy._count) + elif not isinstance(name, str): + raise TypeError('name must be a string') self = object().__new__(cls) self._index = Dummy._count self._name = name.strip() - self._coefficients = {self: 1} - self._constant = 0 + self._coefficients = {self: Fraction(1)} + self._constant = Fraction(0) self._symbols = (self,) self._dimension = 1 Dummy._count += 1 @@ -398,9 +397,6 @@ class Dummy(Symbol): def sortkey(self): return self._name, self._index - def __eq__(self, other): - return isinstance(other, Dummy) and self._index == other._index - def __repr__(self): return '_{}'.format(self.name) @@ -437,30 +433,6 @@ class Rational(Expression, Fraction): def __bool__(self): return Fraction.__bool__(self) - @_polymorphic - def __mul__(self, other): - coefficients = dict(other._coefficients) - for symbol in coefficients: - coefficients[symbol] *= self._constant - constant = other._constant * self._constant - return Expression(coefficients, constant) - - __rmul__ = __mul__ - - @_polymorphic - def __rtruediv__(self, other): - coefficients = dict(other._coefficients) - for symbol in coefficients: - coefficients[symbol] /= self._constant - constant = other._constant / self._constant - return Expression(coefficients, constant) - - @classmethod - def fromstring(cls, string): - if not isinstance(string, str): - raise TypeError('string must be a string instance') - return Rational(string) - def __repr__(self): if self.denominator == 1: return '{!r}'.format(self.numerator)