X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/blobdiff_plain/d4b772a5d2f29c4f54564ea09f5b65289cadcaa1..5eca735504be3b7c301e2a1fa37712eb88b4ec64:/pypol/linexprs.py diff --git a/pypol/linexprs.py b/pypol/linexprs.py index b74628b..07d4005 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 @@ -131,14 +128,14 @@ class Expression: constant = self._constant - other._constant return Expression(coefficients, constant) + @_polymorphic def __rsub__(self, other): - return -(self - other) + return other - self def __mul__(self, other): if isinstance(other, numbers.Rational): - coefficients = dict(self._coefficients) - for symbol in coefficients: - coefficients[symbol] *= other + coefficients = ((symbol, coefficient * other) + for symbol, coefficient in self._coefficients.items()) constant = self._constant * other return Expression(coefficients, constant) return NotImplemented @@ -147,38 +144,32 @@ class Expression: def __truediv__(self, other): if isinstance(other, numbers.Rational): - coefficients = dict(self._coefficients) - for symbol in coefficients: - coefficients[symbol] /= other + coefficients = ((symbol, coefficient / other) + for symbol, coefficient in self._coefficients.items()) constant = self._constant / other - # import pdb; pdb.set_trace() return Expression(coefficients, constant) return NotImplemented @_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) @@ -287,7 +278,7 @@ class Expression: string += ' + {}'.format(constant._repr_latex_().strip('$')) elif constant < 0: string += ' - {}'.format((-constant)._repr_latex_().strip('$')) - return '${}$'.format(string) + return '$${}$$'.format(string) def _parenstr(self, always=False): string = str(self) @@ -349,8 +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) @@ -369,13 +359,15 @@ class Symbol(Expression): return self.name def _repr_latex_(self): - return '${}$'.format(self.name) + return '$${}$$'.format(self.name) @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') @@ -387,6 +379,8 @@ 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() @@ -403,14 +397,11 @@ 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) def _repr_latex_(self): - return '${}_{{{}}}$'.format(self.name, self._index) + return '$${}_{{{}}}$$'.format(self.name, self._index) def symbols(names): @@ -422,11 +413,13 @@ def symbols(names): class Rational(Expression, Fraction): def __new__(cls, numerator=0, denominator=None): - self = Fraction.__new__(cls, numerator, denominator) + self = object().__new__(cls) self._coefficients = {} - self._constant = Fraction(self) + self._constant = Fraction(numerator, denominator) self._symbols = () self._dimension = 0 + self._numerator = self._constant.numerator + self._denominator = self._constant.denominator return self def __hash__(self): @@ -442,12 +435,6 @@ class Rational(Expression, Fraction): def __bool__(self): return Fraction.__bool__(self) - @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) @@ -456,12 +443,12 @@ class Rational(Expression, Fraction): def _repr_latex_(self): if self.denominator == 1: - return '${}$'.format(self.numerator) + return '$${}$$'.format(self.numerator) elif self.numerator < 0: - return '$-\\frac{{{}}}{{{}}}$'.format(-self.numerator, + return '$$-\\frac{{{}}}{{{}}}$$'.format(-self.numerator, self.denominator) else: - return '$\\frac{{{}}}{{{}}}$'.format(self.numerator, + return '$$\\frac{{{}}}{{{}}}$$'.format(self.numerator, self.denominator) @classmethod