X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/blobdiff_plain/2ffea1a47578a1b1d09906d57511062d68e6abea..7b93cea1daf2889e9ee10ca9c22a1b5124404937:/pypol/linexprs.py

diff --git a/pypol/linexprs.py b/pypol/linexprs.py
deleted file mode 100644
index b330045..0000000
--- a/pypol/linexprs.py
+++ /dev/null
@@ -1,514 +0,0 @@
-import ast
-import functools
-import numbers
-import re
-
-from collections import OrderedDict
-from fractions import Fraction, gcd
-
-
-__all__ = [
-    'Expression',
-    'Symbol', 'symbols', 'symbolname', 'symbolnames',
-    'Constant',
-]
-
-
-def _polymorphic(func):
-    @functools.wraps(func)
-    def wrapper(left, right):
-        if isinstance(right, Expression):
-            return func(left, right)
-        elif isinstance(right, numbers.Rational):
-            right = Constant(right)
-            return func(left, right)
-        return NotImplemented
-    return wrapper
-
-
-class Expression:
-    """
-    This class implements linear expressions.
-    """
-
-    __slots__ = (
-        '_coefficients',
-        '_constant',
-        '_symbols',
-        '_dimension',
-        '_hash',
-    )
-
-    def __new__(cls, coefficients=None, constant=0):
-        if isinstance(coefficients, str):
-            if constant:
-                raise TypeError('too many arguments')
-            return cls.fromstring(coefficients)
-        if isinstance(coefficients, dict):
-            coefficients = coefficients.items()
-        if coefficients is None:
-            return Constant(constant)
-        coefficients = [(symbol, coefficient)
-            for symbol, coefficient in coefficients if coefficient != 0]
-        if len(coefficients) == 0:
-            return Constant(constant)
-        elif len(coefficients) == 1 and constant == 0:
-            symbol, coefficient = coefficients[0]
-            if coefficient == 1:
-                return Symbol(symbol)
-        self = object().__new__(cls)
-        self._coefficients = {}
-        for symbol, coefficient in coefficients:
-            symbol = symbolname(symbol)
-            if isinstance(coefficient, Constant):
-                coefficient = coefficient.constant
-            if not isinstance(coefficient, numbers.Rational):
-                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(self._coefficients)
-        self._dimension = len(self._symbols)
-        self._hash = hash((tuple(self._coefficients.items()), self._constant))
-        return self
-
-    def coefficient(self, symbol):
-        symbol = symbolname(symbol)
-        try:
-            return self._coefficients[symbol]
-        except KeyError:
-            return 0
-
-    __getitem__ = coefficient
-
-    def coefficients(self):
-        yield from self._coefficients.items()
-
-    @property
-    def constant(self):
-        return self._constant
-
-    @property
-    def symbols(self):
-        return self._symbols
-
-    @property
-    def dimension(self):
-        return self._dimension
-
-    def __hash__(self):
-        return self._hash
-
-    def isconstant(self):
-        return False
-
-    def issymbol(self):
-        return False
-
-    def values(self):
-        for symbol in self.symbols:
-            yield self.coefficient(symbol)
-        yield self.constant
-
-    def __bool__(self):
-        return True
-
-    def __pos__(self):
-        return self
-
-    def __neg__(self):
-        return self * -1
-
-    @_polymorphic
-    def __add__(self, other):
-        coefficients = dict(self.coefficients())
-        for symbol, coefficient in other.coefficients():
-            if symbol in coefficients:
-                coefficients[symbol] += coefficient
-            else:
-                coefficients[symbol] = coefficient
-        constant = self.constant + other.constant
-        return Expression(coefficients, constant)
-
-    __radd__ = __add__
-
-    @_polymorphic
-    def __sub__(self, other):
-        coefficients = dict(self.coefficients())
-        for symbol, coefficient in other.coefficients():
-            if symbol in coefficients:
-                coefficients[symbol] -= coefficient
-            else:
-                coefficients[symbol] = -coefficient
-        constant = self.constant - other.constant
-        return Expression(coefficients, constant)
-
-    def __rsub__(self, other):
-        return -(self - other)
-
-    @_polymorphic
-    def __mul__(self, other):
-        if other.isconstant():
-            coefficients = dict(self.coefficients())
-            for symbol in coefficients:
-                coefficients[symbol] *= other.constant
-            constant = self.constant * other.constant
-            return Expression(coefficients, constant)
-        if isinstance(other, Expression) and not self.isconstant():
-            raise ValueError('non-linear expression: '
-                    '{} * {}'.format(self._parenstr(), other._parenstr()))
-        return NotImplemented
-
-    __rmul__ = __mul__
-
-    @_polymorphic
-    def __truediv__(self, other):
-        if other.isconstant():
-            coefficients = dict(self.coefficients())
-            for symbol in coefficients:
-                coefficients[symbol] = \
-                        Fraction(coefficients[symbol], other.constant)
-            constant = Fraction(self.constant, other.constant)
-            return Expression(coefficients, constant)
-        if isinstance(other, Expression):
-            raise ValueError('non-linear expression: '
-                '{} / {}'.format(self._parenstr(), other._parenstr()))
-        return NotImplemented
-
-    def __rtruediv__(self, other):
-        if isinstance(other, self):
-            if self.isconstant():
-                constant = Fraction(other, self.constant)
-                return Expression(constant=constant)
-            else:
-                raise ValueError('non-linear expression: '
-                        '{} / {}'.format(other._parenstr(), self._parenstr()))
-        return NotImplemented
-
-    @_polymorphic
-    def __eq__(self, other):
-        # "normal" equality
-        # 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)
-
-    def _toint(self):
-        lcm = functools.reduce(lambda a, b: a*b // gcd(a, b),
-            [value.denominator for value in self.values()])
-        return self * lcm
-
-    @classmethod
-    def _fromast(cls, node):
-        if isinstance(node, ast.Module) and len(node.body) == 1:
-            return cls._fromast(node.body[0])
-        elif isinstance(node, ast.Expr):
-            return cls._fromast(node.value)
-        elif isinstance(node, ast.Name):
-            return Symbol(node.id)
-        elif isinstance(node, ast.Num):
-            return Constant(node.n)
-        elif isinstance(node, ast.UnaryOp) and isinstance(node.op, ast.USub):
-            return -cls._fromast(node.operand)
-        elif isinstance(node, ast.BinOp):
-            left = cls._fromast(node.left)
-            right = cls._fromast(node.right)
-            if isinstance(node.op, ast.Add):
-                return left + right
-            elif isinstance(node.op, ast.Sub):
-                return left - right
-            elif isinstance(node.op, ast.Mult):
-                return left * right
-            elif isinstance(node.op, ast.Div):
-                return left / right
-        raise SyntaxError('invalid syntax')
-
-    def subs(self, symbol, expression=None):
-        if expression is None:
-            if isinstance(symbol, dict):
-                symbol = symbol.items()
-            substitutions = symbol
-        else:
-            substitutions = [(symbol, expression)]
-        result = self
-        for symbol, expression in substitutions:
-            symbol = symbolname(symbol)
-            result = result._subs(symbol, expression)
-        return result
-
-    def _subs(self, symbol, expression):
-        coefficients = {name: coefficient
-            for name, coefficient in self.coefficients()
-            if name != symbol}
-        constant = self.constant
-        coefficient = self.coefficient(symbol)
-        result = Expression(coefficients, self.constant)
-        result += coefficient * expression
-        return result
-
-    _RE_NUM_VAR = re.compile(r'(\d+|\))\s*([^\W\d_]\w*|\()')
-
-    @classmethod
-    def fromstring(cls, string):
-        # add implicit multiplication operators, e.g. '5x' -> '5*x'
-        string = cls._RE_NUM_VAR.sub(r'\1*\2', string)
-        tree = ast.parse(string, 'eval')
-        return cls._fromast(tree)
-
-    def __str__(self):
-        string = ''
-        i = 0
-        for symbol in self.symbols:
-            coefficient = self.coefficient(symbol)
-            if coefficient == 1:
-                if i == 0:
-                    string += symbol
-                else:
-                    string += ' + {}'.format(symbol)
-            elif coefficient == -1:
-                if i == 0:
-                    string += '-{}'.format(symbol)
-                else:
-                    string += ' - {}'.format(symbol)
-            else:
-                if i == 0:
-                    string += '{}*{}'.format(coefficient, symbol)
-                elif coefficient > 0:
-                    string += ' + {}*{}'.format(coefficient, symbol)
-                else:
-                    assert coefficient < 0
-                    coefficient *= -1
-                    string += ' - {}*{}'.format(coefficient, symbol)
-            i += 1
-        constant = self.constant
-        if constant != 0 and i == 0:
-            string += '{}'.format(constant)
-        elif constant > 0:
-            string += ' + {}'.format(constant)
-        elif constant < 0:
-            constant *= -1
-            string += ' - {}'.format(constant)
-        if string == '':
-            string = '0'
-        return string
-
-    def _parenstr(self, always=False):
-        string = str(self)
-        if not always and (self.isconstant() or self.issymbol()):
-            return string
-        else:
-            return '({})'.format(string)
-
-    def __repr__(self):
-        return '{}({!r})'.format(self.__class__.__name__, str(self))
-
-    @classmethod
-    def fromsympy(cls, expr):
-        import sympy
-        coefficients = {}
-        constant = 0
-        for symbol, coefficient in expr.as_coefficients_dict().items():
-            coefficient = Fraction(coefficient.p, coefficient.q)
-            if symbol == sympy.S.One:
-                constant = coefficient
-            elif isinstance(symbol, sympy.Symbol):
-                symbol = symbol.name
-                coefficients[symbol] = coefficient
-            else:
-                raise ValueError('non-linear expression: {!r}'.format(expr))
-        return cls(coefficients, constant)
-
-    def tosympy(self):
-        import sympy
-        expr = 0
-        for symbol, coefficient in self.coefficients():
-            term = coefficient * sympy.Symbol(symbol)
-            expr += term
-        expr += self.constant
-        return expr
-
-
-class Symbol(Expression):
-
-    __slots__ = (
-        '_name',
-        '_hash',
-    )
-
-    def __new__(cls, name):
-        name = symbolname(name)
-        self = object().__new__(cls)
-        self._name = name
-        self._hash = hash(self._name)
-        return self
-
-    @property
-    def name(self):
-        return self._name
-
-    def __hash__(self):
-        return self._hash
-
-    def coefficient(self, symbol):
-        symbol = symbolname(symbol)
-        if symbol == self.name:
-            return 1
-        else:
-            return 0
-
-    def coefficients(self):
-        yield self.name, 1
-
-    @property
-    def constant(self):
-        return 0
-
-    @property
-    def symbols(self):
-        return self.name,
-
-    @property
-    def dimension(self):
-        return 1
-
-    def issymbol(self):
-        return True
-
-    def __eq__(self, other):
-        return isinstance(other, Symbol) and self.name == other.name
-
-    @classmethod
-    def _fromast(cls, node):
-        if isinstance(node, ast.Module) and len(node.body) == 1:
-            return cls._fromast(node.body[0])
-        elif isinstance(node, ast.Expr):
-            return cls._fromast(node.value)
-        elif isinstance(node, ast.Name):
-            return Symbol(node.id)
-        raise SyntaxError('invalid syntax')
-
-    def __repr__(self):
-        return '{}({!r})'.format(self.__class__.__name__, self._name)
-
-    @classmethod
-    def fromsympy(cls, expr):
-        import sympy
-        if isinstance(expr, sympy.Symbol):
-            return cls(expr.name)
-        else:
-            raise TypeError('expr must be a sympy.Symbol instance')
-
-
-def symbols(names):
-    if isinstance(names, str):
-        names = names.replace(',', ' ').split()
-    return (Symbol(name) for name in names)
-
-def symbolname(symbol):
-    if isinstance(symbol, str):
-        return symbol.strip()
-    elif isinstance(symbol, Symbol):
-        return symbol.name
-    else:
-        raise TypeError('symbol must be a string or a Symbol instance')
-
-def symbolnames(symbols):
-    if isinstance(symbols, str):
-        return symbols.replace(',', ' ').split()
-    return (symbolname(symbol) for symbol in symbols)
-
-
-class Constant(Expression):
-
-    __slots__ = (
-        '_constant',
-        '_hash',
-    )
-
-    def __new__(cls, numerator=0, denominator=None):
-        self = object().__new__(cls)
-        if denominator is None and isinstance(numerator, Constant):
-            self._constant = numerator.constant
-        else:
-            self._constant = Fraction(numerator, denominator)
-        self._hash = hash(self._constant)
-        return self
-
-    def __hash__(self):
-        return self._hash
-
-    def coefficient(self, symbol):
-        symbol = symbolname(symbol)
-        return 0
-
-    def coefficients(self):
-        yield from []
-
-    @property
-    def symbols(self):
-        return ()
-
-    @property
-    def dimension(self):
-        return 0
-
-    def isconstant(self):
-        return True
-
-    @_polymorphic
-    def __eq__(self, other):
-        return isinstance(other, Constant) and self.constant == other.constant
-
-    def __bool__(self):
-        return self.constant != 0
-
-    @classmethod
-    def fromstring(cls, string):
-        if isinstance(string, str):
-            return Constant(Fraction(string))
-        else:
-            raise TypeError('string must be a string instance')
-
-    def __repr__(self):
-        if self.constant.denominator == 1:
-            return '{}({!r})'.format(self.__class__.__name__,
-                self.constant.numerator)
-        else:
-            return '{}({!r}, {!r})'.format(self.__class__.__name__,
-                self.constant.numerator, self.constant.denominator)
-
-    @classmethod
-    def fromsympy(cls, expr):
-        import sympy
-        if isinstance(expr, sympy.Rational):
-            return cls(expr.p, expr.q)
-        elif isinstance(expr, numbers.Rational):
-            return cls(expr)
-        else:
-            raise TypeError('expr must be a sympy.Rational instance')