index a0a7b7c..0b05493 100644 (file)
@@ -85,14 +85,15 @@ class Coordinates:
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()):
+        self._coordinates = []
+        for symbol, coordinate in coordinates:
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
+            self._coordinates.append((symbol, coordinate))
+        self._coordinates.sort(key=lambda item: item[0].sortkey())
+        self._coordinates = OrderedDict(self._coordinates)
return self

@property
@@ -141,6 +142,14 @@ class Coordinates:
"""
return any(self._coordinates.values())

+    def __eq__(self, other):
+        """
+        Return True if two coordinate systems are equal.
+        """
+        if isinstance(other, self.__class__):
+            return self._coordinates == other._coordinates
+        return NotImplemented
+
def __hash__(self):
return hash(tuple(self.coordinates()))

@@ -205,14 +214,6 @@ class Point(Coordinates, GeometricObject):
return Point(coordinates)
return NotImplemented

-    def __eq__(self, other):
-        """
-        Test whether two points are equal.
-        """
-        if isinstance(other, Point):
-            return self._coordinates == other._coordinates
-        return NotImplemented
-
def aspolyhedron(self):
from .polyhedra import Polyhedron
equalities = []
@@ -231,7 +232,7 @@ class Vector(Coordinates):
def __new__(cls, initial, terminal=None):
"""
Create a vector from a dictionary or a sequence that maps the symbols to
-        their coordinates, or as the difference between two points.
+        their coordinates, or as the displacement between two points.
"""
if not isinstance(initial, Point):
initial = Point(initial)
@@ -283,10 +284,10 @@ class Vector(Coordinates):
"""
Multiplies a Vector by a scalar value.
"""
-        if not isinstance(other, numbers.Real):
-            return NotImplemented
-        coordinates = self._map(lambda coordinate: other * coordinate)
-        return Vector(coordinates)
+        if isinstance(other, numbers.Real):
+            coordinates = self._map(lambda coordinate: other * coordinate)
+            return Vector(coordinates)
+        return NotImplemented

__rmul__ = __mul__

@@ -295,17 +296,10 @@ class Vector(Coordinates):
Divide the vector by the specified scalar and returns the result as a
vector.
"""
-        if not isinstance(other, numbers.Real):
-            return NotImplemented
-        coordinates = self._map(lambda coordinate: coordinate / other)
-        return Vector(coordinates)
-
-    def __eq__(self, other):
-        """
-        Test whether two vectors are equal.
-        """
-        return isinstance(other, Vector) and \
-            self._coordinates == other._coordinates
+        if isinstance(other, numbers.Real):
+            coordinates = self._map(lambda coordinate: coordinate / other)
+            return Vector(coordinates)
+        return NotImplemented

def angle(self, other):
"""
@@ -321,7 +315,7 @@ class Vector(Coordinates):
def cross(self, other):
"""
Compute the cross product of two 3D vectors. If either one of the
-        vectors is not tridimensional, a ValueError exception is raised.
+        vectors is not three-dimensional, a ValueError exception is raised.
"""
if not isinstance(other, Vector):
raise TypeError('other must be a Vector instance')
@@ -348,7 +342,7 @@ class Vector(Coordinates):
return result

def __hash__(self):
-        return hash(tuple(self.coordinates()))
+        return super().__hash__()

def norm(self):
"""