update

classes/multivector_v2.py

@@ -0,0 +1,164 @@
+"""
+A multi-dimensional ``MultiVector`` class, take 2
+
+A ``MultiVector`` is built from an iterable of numbers::
+
+    >>> MultiVector([3.1, 4.2])
+    MultiVector([3.1, 4.2])
+    >>> MultiVector((3, 4, 5))
+    MultiVector([3.0, 4.0, 5.0])
+    >>> MultiVector(range(10))
+    MultiVector([0.0, 1.0, 2.0, 3.0, 4.0, ...])
+
+
+Tests with 2-dimensions (same results as ``vector_v1.py``)::
+
+    >>> v1 = MultiVector([3, 4])
+    >>> x, y = v1
+    >>> x, y
+    (3.0, 4.0)
+    >>> v1
+    MultiVector([3.0, 4.0])
+    >>> v1_clone = eval(repr(v1))
+    >>> v1 == v1_clone
+    True
+    >>> print(v1)
+    (3.0, 4.0)
+    >>> octets = bytes(v1)
+    >>> octets
+    b'\\x00\\x00\\x00\\x00\\x00\\x00\\x08@\\x00\\x00\\x00\\x00\\x00\\x00\\x10@'
+    >>> abs(v1)
+    5.0
+    >>> bool(v1), bool(MultiVector([0, 0]))
+    (True, False)
+
+
+Test of ``.frombytes()`` class method:
+
+    >>> v1_clone = MultiVector.frombytes(bytes(v1))
+    >>> v1_clone
+    MultiVector([3.0, 4.0])
+    >>> v1 == v1_clone
+    True
+
+
+Tests with 3-dimensions::
+
+    >>> v1 = MultiVector([3, 4, 5])
+    >>> x, y, z = v1
+    >>> x, y, z
+    (3.0, 4.0, 5.0)
+    >>> v1
+    MultiVector([3.0, 4.0, 5.0])
+    >>> v1_clone = eval(repr(v1))
+    >>> v1 == v1_clone
+    True
+    >>> print(v1)
+    (3.0, 4.0, 5.0)
+    >>> abs(v1)  # doctest:+ELLIPSIS
+    7.071067811...
+    >>> bool(v1), bool(MultiVector([0, 0, 0]))
+    (True, False)
+
+
+Tests with many dimensions::
+
+    >>> v7 = MultiVector(range(7))
+    >>> v7
+    MultiVector([0.0, 1.0, 2.0, 3.0, 4.0, ...])
+    >>> abs(v7)  # doctest:+ELLIPSIS
+    9.53939201...
+
+
+Test of ``.__bytes__`` and ``.frombytes()`` methods::
+
+    >>> v1 = MultiVector([3, 4, 5])
+    >>> v1_clone = MultiVector.frombytes(bytes(v1))
+    >>> v1_clone
+    MultiVector([3.0, 4.0, 5.0])
+    >>> v1 == v1_clone
+    True
+
+
+Tests of sequence behavior::
+
+    >>> v1 = MultiVector([3, 4, 5])
+    >>> len(v1)
+    3
+    >>> v1[0], v1[len(v1)-1], v1[-1]
+    (3.0, 5.0, 5.0)
+
+
+Test of slicing::
+
+# BEGIN MULTIVECTOR_V2_DEMO
+
+    >>> v7 = MultiVector(range(7))
+    >>> v7[-1]  # <1>
+    6.0
+    >>> v7[1:4]  # <2>
+    MultiVector([1.0, 2.0, 3.0])
+    >>> v7[-1:]  # <3>
+    MultiVector([6.0])
+    >>> v7[1,2]  # <4>
+    Traceback (most recent call last):
+      ...
+    TypeError: MultiVector indices must be integers
+
+# END MULTIVECTOR_V2_DEMO
+
+"""
+
+from array import array
+import reprlib
+import math
+
+
+class MultiVector:
+    typecode = 'd'
+
+    def __init__(self, components):
+        self._components = array(MultiVector.typecode, components)
+
+    def __iter__(self):
+        return iter(self._components)
+
+    def __repr__(self):
+        components = reprlib.repr(self._components)
+        components = components[components.find('['):-1]
+        return 'MultiVector({})'.format(components)
+
+    def __str__(self):
+        return str(tuple(self))
+
+    def __bytes__(self):
+        return bytes(self._components)
+
+    def __eq__(self, other):
+        return tuple(self) == tuple(other)
+
+    def __abs__(self):
+        return math.sqrt(sum(x * x for x in self))
+
+    def __bool__(self):
+        return bool(abs(self))
+
+# BEGIN MULTIVECTOR_V2
+    def __len__(self):
+        return len(self._components)
+
+    def __getitem__(self, index):
+        cls = type(self)  # <1>
+        if isinstance(index, slice):
+            return cls(self._components[index])  # <2>
+        elif isinstance(index, int):
+            return self._components[index]  # <3>
+        else:
+            msg = '{cls.__name__} indices must be integers'
+            raise TypeError(msg.format(cls=cls))  # <4>
+# END MULTIVECTOR_V2
+
+    @classmethod
+    def frombytes(cls, octets):
+        memv = memoryview(octets).cast(cls.typecode)
+        return cls(memv)