Need to merge

[linpy.git] / pypol / polyhedra.py

diff --git a/pypol/polyhedra.py b/pypol/polyhedra.py
index a5d9495..b0b5d0e 100644 (file)
--- a/pypol/polyhedra.py
+++ b/pypol/polyhedra.py
@@ -56,14 +56,23 @@ class Polyhedron(Domain):
 
     @property
     def equalities(self):
 
     @property
     def equalities(self):

+        """
+        Return a list of the equalities in a set.
+        """

         return self._equalities
 
     @property
     def inequalities(self):
         return self._equalities
 
     @property
     def inequalities(self):

+        """
+        Return a list of the inequalities in a set.
+        """

         return self._inequalities
 
     @property
     def constraints(self):
         return self._inequalities
 
     @property
     def constraints(self):

+        """
+        Return ta list of the constraints of a set.
+        """

         return self._constraints
 
     @property
         return self._constraints
 
     @property


@@ -72,13 +81,13 @@ class Polyhedron(Domain):
 
     def disjoint(self):
         """
 
     def disjoint(self):
         """

-        Return this set as disjoint.
+        Return a set as disjoint.

         """
         return self
 
     def isuniverse(self):
         """
         """
         return self
 
     def isuniverse(self):
         """

-        Return true if this set is the Universe set.
+        Return true if a set is the Universe set.

         """
         islbset = self._toislbasicset(self.equalities, self.inequalities,
             self.symbols)
         """
         islbset = self._toislbasicset(self.equalities, self.inequalities,
             self.symbols)


@@ -88,7 +97,7 @@ class Polyhedron(Domain):
 
     def aspolyhedron(self):
         """
 
     def aspolyhedron(self):
         """

-        Return polyhedral hull of this set.
+        Return polyhedral hull of a set.

         """
         return self
 
         """
         return self
 


@@ -106,12 +115,41 @@ class Polyhedron(Domain):
         return True
 
     def subs(self, symbol, expression=None):
         return True
 
     def subs(self, symbol, expression=None):

+        """
+        Subsitute the given value into an expression and return the resulting
+        expression.
+        """

         equalities = [equality.subs(symbol, expression)
             for equality in self.equalities]
         inequalities = [inequality.subs(symbol, expression)
             for inequality in self.inequalities]
         return Polyhedron(equalities, inequalities)
 
         equalities = [equality.subs(symbol, expression)
             for equality in self.equalities]
         inequalities = [inequality.subs(symbol, expression)
             for inequality in self.inequalities]
         return Polyhedron(equalities, inequalities)
 

+    def _asinequalities(self):
+        inequalities = list(self.equalities)
+        inequalities.extend([-expression for expression in self.equalities])
+        inequalities.extend(self.inequalities)
+        return inequalities
+
+    def widen(self, other):
+        if not isinstance(other, Polyhedron):
+            raise ValueError('argument must be a Polyhedron instance')
+        inequalities1 = self._asinequalities()
+        inequalities2 = other._asinequalities()
+        inequalities = []
+        for inequality1 in inequalities1:
+            if other <= Polyhedron(inequalities=[inequality1]):
+                inequalities.append(inequality1)
+        for inequality2 in inequalities2:
+            for i in range(len(inequalities1)):
+                inequalities3 = inequalities1[:i] + inequalities[i + 1:]
+                inequalities3.append(inequality2)
+                polyhedron3 = Polyhedron(inequalities=inequalities3)
+                if self == polyhedron3:
+                    inequalities.append(inequality2)
+                    break
+        return Polyhedron(inequalities=inequalities)
+

     @classmethod
     def _fromislbasicset(cls, islbset, symbols):
         islconstraints = islhelper.isl_basic_set_constraints(islbset)
     @classmethod
     def _fromislbasicset(cls, islbset, symbols):
         islconstraints = islhelper.isl_basic_set_constraints(islbset)


@@ -184,42 +222,39 @@ class Polyhedron(Domain):
         return domain
 
     def __repr__(self):
         return domain
 
     def __repr__(self):

-        if self.isempty():
-            return 'Empty'
-        elif self.isuniverse():
-            return 'Universe'
+        strings = []
+        for equality in self.equalities:
+            strings.append('Eq({}, 0)'.format(equality))
+        for inequality in self.inequalities:
+            strings.append('Ge({}, 0)'.format(inequality))
+        if len(strings) == 1:
+            return strings[0]

         else:
         else:

-            strings = []
-            for equality in self.equalities:
-                strings.append('Eq({}, 0)'.format(equality))
-            for inequality in self.inequalities:
-                strings.append('Ge({}, 0)'.format(inequality))
-            if len(strings) == 1:
-                return strings[0]
-            else:
-                return 'And({})'.format(', '.join(strings))
+            return 'And({})'.format(', '.join(strings))
+

 
     def _repr_latex_(self):
 
     def _repr_latex_(self):

-        if self.isempty():
-            return '$\\emptyset$'
-        elif self.isuniverse():
-            return '$\\Omega$'
-        else:
-            strings = []
-            for equality in self.equalities:
-                strings.append('{} = 0'.format(equality._repr_latex_().strip('$')))
-            for inequality in self.inequalities:
-                strings.append('{} \\ge 0'.format(inequality._repr_latex_().strip('$')))
-            return '${}$'.format(' \\wedge '.join(strings))
+        strings = []
+        for equality in self.equalities:
+            strings.append('{} = 0'.format(equality._repr_latex_().strip('$')))
+        for inequality in self.inequalities:
+            strings.append('{} \\ge 0'.format(inequality._repr_latex_().strip('$')))
+        return '$${}$$'.format(' \\wedge '.join(strings))

 
     @classmethod
     def fromsympy(cls, expr):
 
     @classmethod
     def fromsympy(cls, expr):

+        """
+        Convert a sympy object to an expression.
+        """

         domain = Domain.fromsympy(expr)
         if not isinstance(domain, Polyhedron):
             raise ValueError('non-polyhedral expression: {!r}'.format(expr))
         return domain
 
     def tosympy(self):
         domain = Domain.fromsympy(expr)
         if not isinstance(domain, Polyhedron):
             raise ValueError('non-polyhedral expression: {!r}'.format(expr))
         return domain
 
     def tosympy(self):

+        """
+        Return an expression as a sympy object.
+        """

         import sympy
         constraints = []
         for equality in self.equalities:
         import sympy
         constraints = []
         for equality in self.equalities:


@@ -228,6 +263,55 @@ class Polyhedron(Domain):
             constraints.append(sympy.Ge(inequality.tosympy(), 0))
         return sympy.And(*constraints)
 
             constraints.append(sympy.Ge(inequality.tosympy(), 0))
         return sympy.And(*constraints)
 

+class EmptyType(Polyhedron):
+
+    __slots__ = Polyhedron.__slots__
+
+    def __new__(cls):
+        self = object().__new__(cls)
+        self._equalities = (Rational(1),)
+        self._inequalities = ()
+        self._constraints = self._equalities
+        self._symbols = ()
+        self._dimension = 0
+        return self
+
+    def widen(self, other):
+        if not isinstance(other, Polyhedron):
+            raise ValueError('argument must be a Polyhedron instance')
+        return other
+
+    def __repr__(self):
+        return 'Empty'
+
+    def _repr_latex_(self):
+        return '$$\\emptyset$$'
+
+Empty = EmptyType()
+
+
+class UniverseType(Polyhedron):
+
+    __slots__ = Polyhedron.__slots__
+
+    def __new__(cls):
+        self = object().__new__(cls)
+        self._equalities = ()
+        self._inequalities = ()
+        self._constraints = ()
+        self._symbols = ()
+        self._dimension = ()
+        return self
+
+    def __repr__(self):
+        return 'Universe'
+
+    def _repr_latex_(self):
+        return '$$\\Omega$$'
+
+Universe = UniverseType()
+
+

 def _polymorphic(func):
     @functools.wraps(func)
     def wrapper(left, right):
 def _polymorphic(func):
     @functools.wraps(func)
     def wrapper(left, right):


@@ -249,46 +333,42 @@ def _polymorphic(func):
 @_polymorphic
 def Lt(left, right):
     """
 @_polymorphic
 def Lt(left, right):
     """

-    Return true if the first set is less than the second.
+    Assert first set is less than the second set.

     """
     return Polyhedron([], [right - left - 1])
 
 @_polymorphic
 def Le(left, right):
     """
     """
     return Polyhedron([], [right - left - 1])
 
 @_polymorphic
 def Le(left, right):
     """

-    Return true the first set is less than or equal to the second.
+    Assert first set is less than or equal to the second set.

     """
     return Polyhedron([], [right - left])
 
 @_polymorphic
 def Eq(left, right):
     """
     """
     return Polyhedron([], [right - left])
 
 @_polymorphic
 def Eq(left, right):
     """

-    Return true if the sets are equal.
+    Assert first set is equal to the second set.

     """
     return Polyhedron([left - right], [])
 
 @_polymorphic
 def Ne(left, right):
     """
     """
     return Polyhedron([left - right], [])
 
 @_polymorphic
 def Ne(left, right):
     """

-    Return true if the sets are NOT equal.
+    Assert first set is not equal to the second set.

     """
     return ~Eq(left, right)
 
 @_polymorphic
 def Gt(left, right):
     """
     """
     return ~Eq(left, right)
 
 @_polymorphic
 def Gt(left, right):
     """

-    Return true if the first set is greater than the second set.
+    Assert first set is greater than the second set.

     """
     return Polyhedron([], [left - right - 1])
 
 @_polymorphic
 def Ge(left, right):
     """
     """
     return Polyhedron([], [left - right - 1])
 
 @_polymorphic
 def Ge(left, right):
     """

-    Return true if the first set is greater than or equal the second set.
+    Assert first set is greater than or equal to the second set.

     """
     return Polyhedron([], [left - right])
 
     """
     return Polyhedron([], [left - right])
 

-
-Empty = Eq(1, 0)
-
-Universe = Polyhedron([])