Implement method Point.aspolyhedron()
[linpy.git] / pypol / coordinates.py
index b5c23c9..7923648 100644 (file)
@@ -2,7 +2,8 @@ import math
 import numbers
 import operator
 
-from collections import OrderedDict
+from abc import ABC, abstractmethod
+from collections import OrderedDict, Mapping
 
 from .linexprs import Symbol
 
@@ -13,40 +14,15 @@ __all__ = [
 ]
 
 
-def _map(obj, func):
-    for symbol, coordinate in obj.coordinates():
-        yield symbol, func(coordinate)
-
-def _iter2(obj1, obj2):
-    if obj1.symbols != obj2.symbols:
-        raise ValueError('arguments must belong to the same space')
-    coordinates1 = obj1._coordinates.values()
-    coordinates2 = obj2._coordinates.values()
-    yield from zip(obj1.symbols, coordinates1, coordinates2)
-
-def _map2(obj1, obj2, func):
-    for symbol, coordinate1, coordinate2 in _iter2(obj1, obj2):
-        yield symbol, func(coordinate1, coordinate2)
+class Coordinates(ABC):
 
+    __slots__ = (
+        '_coordinates',
+    )
 
-class Point:
-    """
-    This class represents points in space.
-    """
-
-    def __new__(cls, coordinates=None):
-        if isinstance(coordinates, dict):
-            coordinates = coordinates.items()
-        self = object().__new__(cls)
-        self._coordinates = OrderedDict()
-        for symbol, coordinate in sorted(coordinates,
-                key=lambda item: item[0].sortkey()):
-            if not isinstance(symbol, Symbol):
-                raise TypeError('symbols must be Symbol instances')
-            if not isinstance(coordinate, numbers.Real):
-                raise TypeError('coordinates must be real numbers')
-            self._coordinates[symbol] = coordinate
-        return self
+    @abstractmethod
+    def __new__(cls):
+        super().__new__(cls)
 
     @property
     def symbols(self):
@@ -66,25 +42,68 @@ class Point:
 
     __getitem__ = coordinate
 
-    def isorigin(self):
-        return not bool(self)
-
     def __bool__(self):
         return any(self._coordinates.values())
 
+    def __hash__(self):
+        return hash(tuple(self.coordinates()))
+
+    def __repr__(self):
+        string = ', '.join(['{!r}: {!r}'.format(symbol, coordinate)
+            for symbol, coordinate in self.coordinates()])
+        return '{}({{{}}})'.format(self.__class__.__name__, string)
+
+    def _map(self, func):
+        for symbol, coordinate in self.coordinates():
+            yield symbol, func(coordinate)
+
+    def _iter2(self, other):
+        if self.symbols != other.symbols:
+            raise ValueError('arguments must belong to the same space')
+        coordinates1 = self._coordinates.values()
+        coordinates2 = other._coordinates.values()
+        yield from zip(self.symbols, coordinates1, coordinates2)
+
+    def _map2(self, other, func):
+        for symbol, coordinate1, coordinate2 in self._iter2(other):
+            yield symbol, func(coordinate1, coordinate2)
+
+
+class Point(Coordinates):
+    """
+    This class represents points in space.
+    """
+
+    def __new__(cls, coordinates=None):
+        if isinstance(coordinates, Mapping):
+            coordinates = coordinates.items()
+        self = object().__new__(cls)
+        self._coordinates = OrderedDict()
+        for symbol, coordinate in sorted(coordinates,
+                key=lambda item: item[0].sortkey()):
+            if not isinstance(symbol, Symbol):
+                raise TypeError('symbols must be Symbol instances')
+            if not isinstance(coordinate, numbers.Real):
+                raise TypeError('coordinates must be real numbers')
+            self._coordinates[symbol] = coordinate
+        return self
+
+    def isorigin(self):
+        return not bool(self)
+
     def __add__(self, other):
         if not isinstance(other, Vector):
             return NotImplemented
-        coordinates = _map2(self, other, operator.add)
+        coordinates = self._map2(other, operator.add)
         return Point(coordinates)
 
     def __sub__(self, other):
         coordinates = []
         if isinstance(other, Point):
-            coordinates = _map2(self, other, operator.sub)
+            coordinates = self._map2(other, operator.sub)
             return Vector(coordinates)
         elif isinstance(other, Vector):
-            coordinates = _map2(self, other, operator.sub)
+            coordinates = self._map2(other, operator.sub)
             return Point(coordinates)
         else:
             return NotImplemented
@@ -93,16 +112,15 @@ class Point:
         return isinstance(other, Point) and \
             self._coordinates == other._coordinates
 
-    def __hash__(self):
-        return hash(tuple(self.coordinates()))
+    def aspolyhedron(self):
+        from .polyhedra import Polyhedron
+        equalities = []
+        for symbol, coordinate in self.coordinates():
+            equalities.append(symbol - coordinate)
+        return Polyhedron(equalities)
 
-    def __repr__(self):
-        string = ', '.join(['{!r}: {!r}'.format(symbol, coordinate)
-            for symbol, coordinate in self.coordinates()])
-        return '{}({{{}}})'.format(self.__class__.__name__, string)
 
-
-class Vector:
+class Vector(Coordinates):
     """
     This class represents displacements in space.
     """
@@ -119,36 +137,15 @@ class Vector:
             self._coordinates = initial._coordinates
         elif not isinstance(terminal, Point):
             terminal = Point(terminal)
-            self._coordinates = _map2(terminal, initial, operator.sub)
+            self._coordinates = terminal._map2(initial, operator.sub)
         return self
 
-    @property
-    def symbols(self):
-        return tuple(self._coordinates)
-
-    @property
-    def dimension(self):
-        return len(self.symbols)
-
-    def coordinates(self):
-        yield from self._coordinates.items()
-
-    def coordinate(self, symbol):
-        if not isinstance(symbol, Symbol):
-            raise TypeError('symbol must be a Symbol instance')
-        return self._coordinates[symbol]
-
-    __getitem__ = coordinate
-
     def isnull(self):
         return not bool(self)
 
-    def __bool__(self):
-        return any(self._coordinates.values())
-
     def __add__(self, other):
         if isinstance(other, (Point, Vector)):
-            coordinates = _map2(self, other, operator.add)
+            coordinates = self._map2(other, operator.add)
             return other.__class__(coordinates)
         return NotImplemented
 
@@ -160,7 +157,7 @@ class Vector:
         """
         if not isinstance(other, Vector):
             raise TypeError('argument must be a Vector instance')
-        cosinus = self.dot(other) / (self.norm() * other.norm())
+        cosinus = self.dot(other) / (self.norm()*other.norm())
         return math.acos(cosinus)
 
     def cross(self, other):
@@ -187,7 +184,7 @@ class Vector:
         """
         if not isinstance(other, numbers.Real):
             return NotImplemented
-        coordinates = _map(self, lambda coordinate: coordinate / other)
+        coordinates = self._map(lambda coordinate: coordinate / other)
         return Vector(coordinates)
 
     def dot(self, other):
@@ -197,7 +194,7 @@ class Vector:
         if not isinstance(other, Vector):
             raise TypeError('argument must be a Vector instance')
         result = 0
-        for symbol, coordinate1, coordinate2 in _iter2(self, other):
+        for symbol, coordinate1, coordinate2 in self._iter2(other):
             result += coordinate1 * coordinate2
         return result
 
@@ -211,13 +208,13 @@ class Vector:
     def __mul__(self, other):
         if not isinstance(other, numbers.Real):
             return NotImplemented
-        coordinates = _map(self, lambda coordinate: other * coordinate)
+        coordinates = self._map(lambda coordinate: other * coordinate)
         return Vector(coordinates)
 
     __rmul__ = __mul__
 
     def __neg__(self):
-        coordinates = _map(self, operator.neg)
+        coordinates = self._map(operator.neg)
         return Vector(coordinates)
 
     def norm(self):
@@ -234,11 +231,6 @@ class Vector:
 
     def __sub__(self, other):
         if isinstance(other, (Point, Vector)):
-            coordinates = _map2(self, other, operator.sub)
+            coordinates = self._map2(other, operator.sub)
             return other.__class__(coordinates)
         return NotImplemented
-
-    def __repr__(self):
-        string = ', '.join(['{!r}: {!r}'.format(symbol, coordinate)
-            for symbol, coordinate in self.coordinates()])
-        return '{}({{{}}})'.format(self.__class__.__name__, string)