Update docstrings to reflect documentation changes

[linpy.git] / linpy / linexprs.py

diff --git a/linpy/linexprs.py b/linpy/linexprs.py
index b5864e1..eff4a7e 100644 (file)
--- a/linpy/linexprs.py
+++ b/linpy/linexprs.py
@@ -62,7 +62,7 @@ class LinExpr:
         symbols to their coefficients, and a constant term. The coefficients and
         the constant term must be rational numbers.
 
         symbols to their coefficients, and a constant term. The coefficients and
         the constant term must be rational numbers.
 

-        For example, the linear expression x + 2y + 1 can be constructed using
+        For example, the linear expression x + 2*y + 1 can be constructed using

         one of the following instructions:
 
         >>> x, y = symbols('x y')
         one of the following instructions:
 
         >>> x, y = symbols('x y')


@@ -76,7 +76,7 @@ class LinExpr:
 
         Alternatively, linear expressions can be constructed from a string:
 
 
         Alternatively, linear expressions can be constructed from a string:
 

-        >>> LinExpr('x + 2*y + 1')
+        >>> LinExpr('x + 2y + 1')

 
         A linear expression with a single symbol of coefficient 1 and no
         constant term is automatically subclassed as a Symbol instance. A linear
 
         A linear expression with a single symbol of coefficient 1 and no
         constant term is automatically subclassed as a Symbol instance. A linear


@@ -245,28 +245,34 @@ class LinExpr:
     @_polymorphic
     def __eq__(self, other):
         """
     @_polymorphic
     def __eq__(self, other):
         """

-        Test whether two linear expressions are equal.
+        Test whether two linear expressions are equal. Unlike methods
+        LinExpr.__lt__(), LinExpr.__le__(), LinExpr.__ge__(), LinExpr.__gt__(),
+        the result is a boolean value, not a polyhedron. To express that two
+        linear expressions are equal or not equal, use functions Eq() and Ne()
+        instead.

         """
         """

-        if isinstance(other, LinExpr):
-            return self._coefficients == other._coefficients and \
-                self._constant == other._constant
-        return NotImplemented
-
-    def __le__(self, other):
-        from .polyhedra import Le
-        return Le(self, other)
+        return self._coefficients == other._coefficients and \
+            self._constant == other._constant

 
 

+    @_polymorphic

     def __lt__(self, other):
     def __lt__(self, other):

-        from .polyhedra import Lt
-        return Lt(self, other)
+        from .polyhedra import Polyhedron
+        return Polyhedron([], [other - self - 1])

 
 

+    @_polymorphic
+    def __le__(self, other):
+        from .polyhedra import Polyhedron
+        return Polyhedron([], [other - self])
+
+    @_polymorphic

     def __ge__(self, other):
     def __ge__(self, other):

-        from .polyhedra import Ge
-        return Ge(self, other)
+        from .polyhedra import Polyhedron
+        return Polyhedron([], [self - other])

 
 

+    @_polymorphic

     def __gt__(self, other):
     def __gt__(self, other):

-        from .polyhedra import Gt
-        return Gt(self, other)
+        from .polyhedra import Polyhedron
+        return Polyhedron([], [self - other - 1])

 
     def scaleint(self):
         """
 
     def scaleint(self):
         """


@@ -331,7 +337,7 @@ class LinExpr:
                 return left / right
         raise SyntaxError('invalid syntax')
 
                 return left / right
         raise SyntaxError('invalid syntax')
 

-    _RE_NUM_VAR = re.compile(r'(\d+|\))\s*([^\W\d_]\w*|\()')
+    _RE_NUM_VAR = re.compile(r'(\d+|\))\s*([^\W\d]\w*|\()')

 
     @classmethod
     def fromstring(cls, string):
 
     @classmethod
     def fromstring(cls, string):


@@ -339,7 +345,7 @@ class LinExpr:
         Create an expression from a string. Raise SyntaxError if the string is
         not properly formatted.
         """
         Create an expression from a string. Raise SyntaxError if the string is
         not properly formatted.
         """

-        # add implicit multiplication operators, e.g. '5x' -> '5*x'
+        # Add implicit multiplication operators, e.g. '5x' -> '5*x'.

         string = LinExpr._RE_NUM_VAR.sub(r'\1*\2', string)
         tree = ast.parse(string, 'eval')
         expr = cls._fromast(tree)
         string = LinExpr._RE_NUM_VAR.sub(r'\1*\2', string)
         tree = ast.parse(string, 'eval')
         expr = cls._fromast(tree)


@@ -405,7 +411,7 @@ class LinExpr:
     @classmethod
     def fromsympy(cls, expr):
         """
     @classmethod
     def fromsympy(cls, expr):
         """

-        Create a linear expression from a sympy expression. Raise TypeError is
+        Create a linear expression from a SymPy expression. Raise TypeError is

         the sympy expression is not linear.
         """
         import sympy
         the sympy expression is not linear.
         """
         import sympy


@@ -416,7 +422,8 @@ class LinExpr:
             if symbol == sympy.S.One:
                 constant = coefficient
             elif isinstance(symbol, sympy.Dummy):
             if symbol == sympy.S.One:
                 constant = coefficient
             elif isinstance(symbol, sympy.Dummy):

-                # we cannot properly convert dummy symbols
+                # We cannot properly convert dummy symbols with respect to
+                # symbol equalities.

                 raise TypeError('cannot convert dummy symbols')
             elif isinstance(symbol, sympy.Symbol):
                 symbol = Symbol(symbol.name)
                 raise TypeError('cannot convert dummy symbols')
             elif isinstance(symbol, sympy.Symbol):
                 symbol = Symbol(symbol.name)


@@ -430,7 +437,7 @@ class LinExpr:
 
     def tosympy(self):
         """
 
     def tosympy(self):
         """

-        Convert the linear expression to a sympy expression.
+        Convert the linear expression to a SymPy expression.

         """
         import sympy
         expr = 0
         """
         import sympy
         expr = 0


@@ -450,6 +457,13 @@ class Symbol(LinExpr):
     Two instances of Symbol are equal if they have the same name.
     """
 
     Two instances of Symbol are equal if they have the same name.
     """
 

+    __slots__ = (
+        '_name',
+        '_constant',
+        '_symbols',
+        '_dimension',
+    )
+

     def __new__(cls, name):
         """
         Return a symbol with the name string given in argument.
     def __new__(cls, name):
         """
         Return a symbol with the name string given in argument.


@@ -463,12 +477,17 @@ class Symbol(LinExpr):
             raise SyntaxError('invalid syntax')
         self = object().__new__(cls)
         self._name = name
             raise SyntaxError('invalid syntax')
         self = object().__new__(cls)
         self._name = name

-        self._coefficients = {self: Fraction(1)}

         self._constant = Fraction(0)
         self._symbols = (self,)
         self._dimension = 1
         return self
 
         self._constant = Fraction(0)
         self._symbols = (self,)
         self._dimension = 1
         return self
 

+    @property
+    def _coefficients(self):
+        # This is not implemented as an attribute, because __hash__ is not
+        # callable in __new__ in class Dummy.
+        return {self: Fraction(1)}
+

     @property
     def name(self):
         """
     @property
     def name(self):
         """


@@ -553,15 +572,8 @@ class Dummy(Symbol):
         """
         if name is None:
             name = 'Dummy_{}'.format(Dummy._count)
         """
         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 = super().__new__(cls, name)

         self._index = Dummy._count
         self._index = Dummy._count

-        self._name = name.strip()
-        self._coefficients = {self: Fraction(1)}
-        self._constant = Fraction(0)
-        self._symbols = (self,)
-        self._dimension = 1

         Dummy._count += 1
         return self
 
         Dummy._count += 1
         return self
 


@@ -586,6 +598,13 @@ class Rational(LinExpr, Fraction):
     fractions.Fraction classes.
     """
 
     fractions.Fraction classes.
     """
 

+    __slots__ = (
+        '_coefficients',
+        '_constant',
+        '_symbols',
+        '_dimension',
+    ) + Fraction.__slots__
+

     def __new__(cls, numerator=0, denominator=None):
         self = object().__new__(cls)
         self._coefficients = {}
     def __new__(cls, numerator=0, denominator=None):
         self = object().__new__(cls)
         self._coefficients = {}