Cleaner implementation of Rational

[linpy.git] / pypol / polyhedra.py

diff --git a/pypol/polyhedra.py b/pypol/polyhedra.py
index db99753..e745d7d 100644 (file)
--- a/pypol/polyhedra.py
+++ b/pypol/polyhedra.py
@@ -1,10 +1,11 @@
-
 import functools
+import math
 import numbers
 
 from . import islhelper
 
 from .islhelper import mainctx, libisl
+from .geometry import GeometricObject, Point, Vector
 from .linexprs import Expression, Symbol, Rational
 from .domains import Domain
 
@@ -31,11 +32,7 @@ class Polyhedron(Domain):
             if inequalities is not None:
                 raise TypeError('too many arguments')
             return cls.fromstring(equalities)
-        elif isinstance(equalities, Polyhedron):
-            if inequalities is not None:
-                raise TypeError('too many arguments')
-            return equalities
-        elif isinstance(equalities, Domain):
+        elif isinstance(equalities, GeometricObject):
             if inequalities is not None:
                 raise TypeError('too many arguments')
             return equalities.aspolyhedron()
@@ -86,6 +83,19 @@ class Polyhedron(Domain):
     def aspolyhedron(self):
         return self
 
+    def __contains__(self, point):
+        if not isinstance(point, Point):
+            raise TypeError('point must be a Point instance')
+        if self.symbols != point.symbols:
+            raise ValueError('arguments must belong to the same space')
+        for equality in self.equalities:
+            if equality.subs(point.coordinates()) != 0:
+                return False
+        for inequality in self.inequalities:
+            if inequality.subs(point.coordinates()) < 0:
+                return False
+        return True
+
     def subs(self, symbol, expression=None):
         equalities = [equality.subs(symbol, expression)
             for equality in self.equalities]
@@ -195,19 +205,81 @@ class Polyhedron(Domain):
         for inequality in self.inequalities:
             constraints.append(sympy.Ge(inequality.tosympy(), 0))
         return sympy.And(*constraints)
-    
+
+    @classmethod
+    def _polygon_inner_point(cls, points):
+        symbols = points[0].symbols
+        coordinates = {symbol: 0 for symbol in symbols}
+        for point in points:
+            for symbol, coordinate in point.coordinates():
+                coordinates[symbol] += coordinate
+        for symbol in symbols:
+            coordinates[symbol] /= len(points)
+        return Point(coordinates)
+
+    @classmethod
+    def _sort_polygon_2d(cls, points):
+        if len(points) <= 3:
+            return points
+        o = cls._polygon_inner_point(points)
+        angles = {}
+        for m in points:
+            om = Vector(o, m)
+            dx, dy = (coordinate for symbol, coordinate in om.coordinates())
+            angle = math.atan2(dy, dx)
+            angles[m] = angle
+        return sorted(points, key=angles.get)
+
+    @classmethod
+    def _sort_polygon_3d(cls, points):
+        if len(points) <= 3:
+            return points
+        o = cls._polygon_inner_point(points)
+        a = points[0]
+        oa = Vector(o, a)
+        norm_oa = oa.norm()
+        for b in points[1:]:
+            ob = Vector(o, b)
+            u = oa.cross(ob)
+            if not u.isnull():
+                u = u.asunit()
+                break
+        else:
+            raise ValueError('degenerate polygon')
+        angles = {a: 0.}
+        for m in points[1:]:
+            om = Vector(o, m)
+            normprod = norm_oa * om.norm()
+            cosinus = oa.dot(om) / normprod
+            sinus = u.dot(oa.cross(om)) / normprod
+            angle = math.acos(cosinus)
+            angle = math.copysign(angle, sinus)
+            angles[m] = angle
+        return sorted(points, key=angles.get)
+
+    def faces(self):
+        vertices = self.vertices()
+        faces = []
+        for constraint in self.constraints:
+            face = []
+            for vertex in vertices:
+                if constraint.subs(vertex.coordinates()) == 0:
+                    face.append(vertex)
+            faces.append(face)
+        return faces
+
     def plot(self):
         import matplotlib.pyplot as plt
         from matplotlib.path import Path
         import matplotlib.patches as patches
-        
+
         if len(self.symbols)> 3:
             raise TypeError
-        
+
         elif len(self.symbols) == 2:
             verts = self.vertices()
             points = []
-            codes = [Path.MOVETO]   
+            codes = [Path.MOVETO]
             for vert in verts:
                 pairs = ()
                 for sym in sorted(vert, key=Symbol.sortkey):
@@ -229,26 +301,28 @@ class Polyhedron(Domain):
             ax.set_xlim(-5,5)
             ax.set_ylim(-5,5)
             plt.show()
-            
+
         elif len(self.symbols)==3:
             return 0
-            
+
         return points
 
 
 def _polymorphic(func):
     @functools.wraps(func)
     def wrapper(left, right):
-        if isinstance(left, numbers.Rational):
-            left = Rational(left)
-        elif not isinstance(left, Expression):
-            raise TypeError('left must be a a rational number '
-                'or a linear expression')
-        if isinstance(right, numbers.Rational):
-            right = Rational(right)
-        elif not isinstance(right, Expression):
-            raise TypeError('right must be a a rational number '
-                'or a linear expression')
+        if not isinstance(left, Expression):
+            if isinstance(left, numbers.Rational):
+                left = Rational(left)
+            else:
+                raise TypeError('left must be a a rational number '
+                    'or a linear expression')
+        if not isinstance(right, Expression):
+            if isinstance(right, numbers.Rational):
+                right = Rational(right)
+            else:
+                raise TypeError('right must be a a rational number '
+                    'or a linear expression')
         return func(left, right)
     return wrapper