Fix error message

[linpy.git] / linpy / geometry.py

diff --git a/linpy/geometry.py b/linpy/geometry.py
index 5b5ed89..80f7771 100644 (file)
--- a/linpy/geometry.py
+++ b/linpy/geometry.py
@@ -19,8 +19,8 @@ import math
 import numbers
 import operator
 
-from abc import ABC, abstractproperty, abstractmethod
-from collections import OrderedDict, Mapping
+from abc import ABC, abstractmethod, abstractproperty
+from collections import Mapping, OrderedDict
 
 from .linexprs import Symbol
 
@@ -79,20 +79,21 @@ class Coordinates:
 
     def __new__(cls, coordinates):
         """
-        Create a coordinate system from a dictionary or a sequence that maps the
-        symbols to their coordinates. Coordinates must be rational numbers.
+        Create a coordinate system from a dictionary or a sequence that maps
+        the symbols to their coordinates. Coordinates must be rational numbers.
         """
         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
@@ -141,12 +142,20 @@ 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()))
 
     def __repr__(self):
         string = ', '.join(['{!r}: {!r}'.format(symbol, coordinate)
-            for symbol, coordinate in self.coordinates()])
+                            for symbol, coordinate in self.coordinates()])
         return '{}({{{}}})'.format(self.__class__.__name__, string)
 
     def _map(self, func):
@@ -185,16 +194,16 @@ class Point(Coordinates, GeometricObject):
         """
         Translate the point by a Vector object and return the resulting point.
         """
-        if not isinstance(other, Vector):
-            return NotImplemented
-        coordinates = self._map2(other, operator.add)
-        return Point(coordinates)
+        if isinstance(other, Vector):
+            coordinates = self._map2(other, operator.add)
+            return Point(coordinates)
+        return NotImplemented
 
     def __sub__(self, other):
         """
         If other is a point, substract it from self and return the resulting
-        vector. If other is a vector, translate the point by the opposite vector
-        and returns the resulting point.
+        vector. If other is a vector, translate the point by the opposite
+        vector and returns the resulting point.
         """
         coordinates = []
         if isinstance(other, Point):
@@ -203,15 +212,7 @@ class Point(Coordinates, GeometricObject):
         elif isinstance(other, Vector):
             coordinates = self._map2(other, operator.sub)
             return Point(coordinates)
-        else:
-            return NotImplemented
-
-    def __eq__(self, other):
-        """
-        Test whether two points are equal.
-        """
-        return isinstance(other, Point) and \
-            self._coordinates == other._coordinates
+        return NotImplemented
 
     def aspolyhedron(self):
         from .polyhedra import Polyhedron
@@ -230,8 +231,8 @@ 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.
+        Create a vector from a dictionary or a sequence that maps the symbols
+        to 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')
@@ -347,9 +341,6 @@ class Vector(Coordinates):
             result += coordinate1 * coordinate2
         return result
 
-    def __hash__(self):
-        return hash(tuple(self.coordinates()))
-
     def norm(self):
         """
         Return the norm of the vector.
@@ -367,7 +358,7 @@ class Vector(Coordinates):
 
     def asunit(self):
         """
-        Return the normalized vector, i.e. the vector of same direction but with
-        norm 1.
+        Return the normalized vector, i.e. the vector of same direction but
+        with norm 1.
         """
         return self / self.norm()