Add method Polyhedron.asinequalities()

[linpy.git] / linpy / polyhedra.py

diff --git a/linpy/polyhedra.py b/linpy/polyhedra.py
index 9fdf6e7..b88cfd1 100644 (file)
--- a/linpy/polyhedra.py
+++ b/linpy/polyhedra.py
@@ -144,6 +144,15 @@ class Polyhedron(Domain):
     def aspolyhedron(self):
         return self
 
     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')
     def __contains__(self, point):
         if not isinstance(point, Point):
             raise TypeError('point must be a Point instance')


@@ -164,7 +173,11 @@ class Polyhedron(Domain):
             for inequality in self.inequalities]
         return Polyhedron(equalities, inequalities)
 
             for inequality in self.inequalities]
         return Polyhedron(equalities, inequalities)
 

-    def _asinequalities(self):
+    def asinequalities(self):
+        """
+        Express the polyhedron using inequalities, given as a list of
+        expressions greater or equal to 0.
+        """

         inequalities = list(self.equalities)
         inequalities.extend([-expression for expression in self.equalities])
         inequalities.extend(self.inequalities)
         inequalities = list(self.equalities)
         inequalities.extend([-expression for expression in self.equalities])
         inequalities.extend(self.inequalities)


@@ -178,9 +191,9 @@ class Polyhedron(Domain):
         used on large polyhedra.
         """
         if not isinstance(other, Polyhedron):
         used on large polyhedra.
         """
         if not isinstance(other, Polyhedron):

-            raise ValueError('argument must be a Polyhedron instance')
-        inequalities1 = self._asinequalities()
-        inequalities2 = other._asinequalities()
+            raise TypeError('argument must be a Polyhedron instance')
+        inequalities1 = self.asinequalities()
+        inequalities2 = other.asinequalities()

         inequalities = []
         for inequality1 in inequalities1:
             if other <= Polyhedron(inequalities=[inequality1]):
         inequalities = []
         for inequality1 in inequalities1:
             if other <= Polyhedron(inequalities=[inequality1]):


@@ -306,8 +319,6 @@ class EmptyType(Polyhedron):
     The empty polyhedron, whose set of constraints is not satisfiable.
     """
 
     The empty polyhedron, whose set of constraints is not satisfiable.
     """
 

-    __slots__ = Polyhedron.__slots__
-

     def __new__(cls):
         self = object().__new__(cls)
         self._equalities = (Rational(1),)
     def __new__(cls):
         self = object().__new__(cls)
         self._equalities = (Rational(1),)


@@ -336,8 +347,6 @@ class UniverseType(Polyhedron):
     i.e. is empty.
     """
 
     i.e. is empty.
     """
 

-    __slots__ = Polyhedron.__slots__
-

     def __new__(cls):
         self = object().__new__(cls)
         self._equalities = ()
     def __new__(cls):
         self = object().__new__(cls)
         self._equalities = ()


@@ -403,15 +412,15 @@ def Ne(left, right):
     return ~Eq(left, right)
 
 @_polymorphic
     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
 
 @_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])