index 8426d32..50af053 100644 (file)
@@ -144,6 +144,15 @@ class Polyhedron(Domain):
def aspolyhedron(self):
return self

+    def convex_union(self, *others):
+        """
+        Return the convex union of two or more polyhedra.
+        """
+        for other in others:
+            if not isinstance(other, Polyhedron):
+                raise TypeError('arguments must be Polyhedron instances')
+        return Polyhedron(self.union(*others))
+
def __contains__(self, point):
if not isinstance(point, Point):
raise TypeError('point must be a Point instance')
@@ -173,9 +182,12 @@ class Polyhedron(Domain):
def widen(self, other):
"""
Compute the standard widening of two polyhedra, à la Halbwachs.
+
+        In its current implementation, this method is slow and should not be
+        used on large polyhedra.
"""
if not isinstance(other, Polyhedron):
-            raise ValueError('argument must be a Polyhedron instance')
+            raise TypeError('argument must be a Polyhedron instance')
inequalities1 = self._asinequalities()
inequalities2 = other._asinequalities()
inequalities = []
@@ -303,8 +315,6 @@ class EmptyType(Polyhedron):
The empty polyhedron, whose set of constraints is not satisfiable.
"""

-    __slots__ = Polyhedron.__slots__
-
def __new__(cls):
self = object().__new__(cls)
self._equalities = (Rational(1),)
@@ -333,8 +343,6 @@ class UniverseType(Polyhedron):
i.e. is empty.
"""

-    __slots__ = Polyhedron.__slots__
-
def __new__(cls):
self = object().__new__(cls)
self._equalities = ()
@@ -400,15 +408,15 @@ def Ne(left, right):
return ~Eq(left, right)

@_polymorphic
-def Gt(left, right):
+def Ge(left, right):
"""
-    Create the polyhedron with constraints expr1 > expr2 > expr3 ...
+    Create the polyhedron with constraints expr1 >= expr2 >= expr3 ...
"""
-    return Polyhedron([], [left - right - 1])
+    return Polyhedron([], [left - right])

@_polymorphic
-def Ge(left, right):
+def Gt(left, right):
"""
-    Create the polyhedron with constraints expr1 >= expr2 >= expr3 ...
+    Create the polyhedron with constraints expr1 > expr2 > expr3 ...
"""
-    return Polyhedron([], [left - right])
+    return Polyhedron([], [left - right - 1])