|
| 1 | +""" |
| 2 | +A multi-dimensional ``MultiVector`` class, take 2 |
| 3 | +
|
| 4 | +A ``MultiVector`` is built from an iterable of numbers:: |
| 5 | +
|
| 6 | + >>> MultiVector([3.1, 4.2]) |
| 7 | + MultiVector([3.1, 4.2]) |
| 8 | + >>> MultiVector((3, 4, 5)) |
| 9 | + MultiVector([3.0, 4.0, 5.0]) |
| 10 | + >>> MultiVector(range(10)) |
| 11 | + MultiVector([0.0, 1.0, 2.0, 3.0, 4.0, ...]) |
| 12 | +
|
| 13 | +
|
| 14 | +Tests with 2-dimensions (same results as ``vector_v1.py``):: |
| 15 | +
|
| 16 | + >>> v1 = MultiVector([3, 4]) |
| 17 | + >>> x, y = v1 |
| 18 | + >>> x, y |
| 19 | + (3.0, 4.0) |
| 20 | + >>> v1 |
| 21 | + MultiVector([3.0, 4.0]) |
| 22 | + >>> v1_clone = eval(repr(v1)) |
| 23 | + >>> v1 == v1_clone |
| 24 | + True |
| 25 | + >>> print(v1) |
| 26 | + (3.0, 4.0) |
| 27 | + >>> octets = bytes(v1) |
| 28 | + >>> octets |
| 29 | + b'\\x00\\x00\\x00\\x00\\x00\\x00\\x08@\\x00\\x00\\x00\\x00\\x00\\x00\\x10@' |
| 30 | + >>> abs(v1) |
| 31 | + 5.0 |
| 32 | + >>> bool(v1), bool(MultiVector([0, 0])) |
| 33 | + (True, False) |
| 34 | +
|
| 35 | +
|
| 36 | +Test of ``.frombytes()`` class method: |
| 37 | +
|
| 38 | + >>> v1_clone = MultiVector.frombytes(bytes(v1)) |
| 39 | + >>> v1_clone |
| 40 | + MultiVector([3.0, 4.0]) |
| 41 | + >>> v1 == v1_clone |
| 42 | + True |
| 43 | +
|
| 44 | +
|
| 45 | +Tests with 3-dimensions:: |
| 46 | +
|
| 47 | + >>> v1 = MultiVector([3, 4, 5]) |
| 48 | + >>> x, y, z = v1 |
| 49 | + >>> x, y, z |
| 50 | + (3.0, 4.0, 5.0) |
| 51 | + >>> v1 |
| 52 | + MultiVector([3.0, 4.0, 5.0]) |
| 53 | + >>> v1_clone = eval(repr(v1)) |
| 54 | + >>> v1 == v1_clone |
| 55 | + True |
| 56 | + >>> print(v1) |
| 57 | + (3.0, 4.0, 5.0) |
| 58 | + >>> abs(v1) # doctest:+ELLIPSIS |
| 59 | + 7.071067811... |
| 60 | + >>> bool(v1), bool(MultiVector([0, 0, 0])) |
| 61 | + (True, False) |
| 62 | +
|
| 63 | +
|
| 64 | +Tests with many dimensions:: |
| 65 | +
|
| 66 | + >>> v7 = MultiVector(range(7)) |
| 67 | + >>> v7 |
| 68 | + MultiVector([0.0, 1.0, 2.0, 3.0, 4.0, ...]) |
| 69 | + >>> abs(v7) # doctest:+ELLIPSIS |
| 70 | + 9.53939201... |
| 71 | +
|
| 72 | +
|
| 73 | +Test of ``.__bytes__`` and ``.frombytes()`` methods:: |
| 74 | +
|
| 75 | + >>> v1 = MultiVector([3, 4, 5]) |
| 76 | + >>> v1_clone = MultiVector.frombytes(bytes(v1)) |
| 77 | + >>> v1_clone |
| 78 | + MultiVector([3.0, 4.0, 5.0]) |
| 79 | + >>> v1 == v1_clone |
| 80 | + True |
| 81 | +
|
| 82 | +
|
| 83 | +Tests of sequence behavior:: |
| 84 | +
|
| 85 | + >>> v1 = MultiVector([3, 4, 5]) |
| 86 | + >>> len(v1) |
| 87 | + 3 |
| 88 | + >>> v1[0], v1[len(v1)-1], v1[-1] |
| 89 | + (3.0, 5.0, 5.0) |
| 90 | +
|
| 91 | +
|
| 92 | +Test of slicing:: |
| 93 | +
|
| 94 | + >>> v7 = MultiVector(range(7)) |
| 95 | + >>> v7[-1] |
| 96 | + 6.0 |
| 97 | + >>> v7[1:4] |
| 98 | + MultiVector([1.0, 2.0, 3.0]) |
| 99 | + >>> v7[-1:] |
| 100 | + MultiVector([6.0]) |
| 101 | + >>> v7[1,2] |
| 102 | + Traceback (most recent call last): |
| 103 | + ... |
| 104 | + TypeError: MultiVector indices must be integers |
| 105 | +
|
| 106 | +
|
| 107 | +Tests of dynamic attribute access:: |
| 108 | +
|
| 109 | + >>> v7 = MultiVector(range(10)) |
| 110 | + >>> v7.x |
| 111 | + 0.0 |
| 112 | + >>> v7.y, v7.z, v7.t, v7.u, v7.v, v7.w |
| 113 | + (1.0, 2.0, 3.0, 4.0, 5.0, 6.0) |
| 114 | +
|
| 115 | +Dynamic attribute lookup failures:: |
| 116 | +
|
| 117 | + >>> v7.k |
| 118 | + Traceback (most recent call last): |
| 119 | + ... |
| 120 | + AttributeError: 'MultiVector' object has no attribute 'k' |
| 121 | + >>> v3 = MultiVector(range(3)) |
| 122 | + >>> v3.t |
| 123 | + Traceback (most recent call last): |
| 124 | + ... |
| 125 | + AttributeError: 'MultiVector' object has no attribute 't' |
| 126 | + >>> v3.spam |
| 127 | + Traceback (most recent call last): |
| 128 | + ... |
| 129 | + AttributeError: 'MultiVector' object has no attribute 'spam' |
| 130 | +
|
| 131 | +
|
| 132 | +Tests of hashing:: |
| 133 | +
|
| 134 | + >>> v1 = MultiVector([3, 4]) |
| 135 | + >>> v2 = MultiVector([3.1, 4.2]) |
| 136 | + >>> v3 = MultiVector([3, 4, 5]) |
| 137 | + >>> v6 = MultiVector(range(6)) |
| 138 | + >>> hash(v1), hash(v2), hash(v3), hash(v6) |
| 139 | + (7, 384307168202284039, 2, 1) |
| 140 | + >>> len(set([v1, v2, v3, v6])) |
| 141 | + 4 |
| 142 | +
|
| 143 | +
|
| 144 | +Tests of ``format()`` with Cartesian coordinates in 2D: |
| 145 | +
|
| 146 | + >>> v1 = MultiVector([3, 4]) |
| 147 | + >>> format(v1) |
| 148 | + '(3.0, 4.0)' |
| 149 | + >>> format(v1, '.2f') |
| 150 | + '(3.00, 4.00)' |
| 151 | + >>> format(v1, '.3e') |
| 152 | + '(3.000e+00, 4.000e+00)' |
| 153 | +
|
| 154 | +
|
| 155 | +Tests of ``format()`` with Cartesian coordinates in 3D and 7D: |
| 156 | +
|
| 157 | + >>> v3 = MultiVector([3, 4, 5]) |
| 158 | + >>> format(v3) |
| 159 | + '(3.0, 4.0, 5.0)' |
| 160 | + >>> format(MultiVector(range(7))) |
| 161 | + '(0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0)' |
| 162 | +
|
| 163 | +
|
| 164 | +Tests of the ``angle`` method:: |
| 165 | +
|
| 166 | + >>> MultiVector([0, 0]).angle() |
| 167 | + 0.0 |
| 168 | + >>> MultiVector([1, 0]).angle() |
| 169 | + 0.0 |
| 170 | + >>> epsilon = 10**-8 |
| 171 | + >>> abs(MultiVector([0, 1]).angle() - math.pi/2) < epsilon |
| 172 | + True |
| 173 | + >>> abs(MultiVector([1, 1]).angle() - math.pi/4) < epsilon |
| 174 | + True |
| 175 | +
|
| 176 | +
|
| 177 | +Tests of ``format()`` with polar coordinates: |
| 178 | +
|
| 179 | + >>> format(MultiVector([1, 1]), 'p') # doctest:+ELLIPSIS |
| 180 | + '<1.414213..., 0.785398...>' |
| 181 | + >>> format(MultiVector([1, 1]), '.3ep') |
| 182 | + '<1.414e+00, 7.854e-01>' |
| 183 | + >>> format(MultiVector([1, 1]), '0.5fp') |
| 184 | + '<1.41421, 0.78540>' |
| 185 | +
|
| 186 | +
|
| 187 | +""" |
| 188 | + |
| 189 | +from array import array |
| 190 | +import reprlib |
| 191 | +import math |
| 192 | +import functools |
| 193 | +import operator |
| 194 | + |
| 195 | + |
| 196 | +class MultiVector: |
| 197 | + typecode = 'd' |
| 198 | + |
| 199 | + def __init__(self, components): |
| 200 | + self._components = array(self.typecode, components) |
| 201 | + |
| 202 | + def __iter__(self): |
| 203 | + return iter(self._components) |
| 204 | + |
| 205 | + def __repr__(self): |
| 206 | + components = reprlib.repr(self._components) |
| 207 | + components = components[components.find('['):-1] |
| 208 | + return 'MultiVector({})'.format(components) |
| 209 | + |
| 210 | + def __str__(self): |
| 211 | + return str(tuple(self)) |
| 212 | + |
| 213 | + def __bytes__(self): |
| 214 | + return bytes(self._components) |
| 215 | + |
| 216 | + def __eq__(self, other): |
| 217 | + return tuple(self) == tuple(other) |
| 218 | + |
| 219 | + def __hash__(self): |
| 220 | + hashes = (hash(x) for x in self) |
| 221 | + return functools.reduce(operator.xor, hashes) |
| 222 | + |
| 223 | + def __abs__(self): |
| 224 | + return math.sqrt(sum(x * x for x in self)) |
| 225 | + |
| 226 | + def __bool__(self): |
| 227 | + return bool(abs(self)) |
| 228 | + |
| 229 | + def __len__(self): |
| 230 | + return len(self._components) |
| 231 | + |
| 232 | + def __getitem__(self, index): |
| 233 | + cls = type(self) |
| 234 | + if isinstance(index, slice): |
| 235 | + return cls(self._components[index]) |
| 236 | + elif isinstance(index, int): |
| 237 | + return self._components[index] |
| 238 | + else: |
| 239 | + msg = '{.__name__} indices must be integers' |
| 240 | + raise TypeError(msg.format(cls)) |
| 241 | + |
| 242 | + shortcut_names = 'xyztuvw' |
| 243 | + |
| 244 | + def __getattr__(self, name): |
| 245 | + cls = type(self) |
| 246 | + if len(name) == 1: |
| 247 | + pos = cls.shortcut_names.find(name) |
| 248 | + if 0 <= pos < len(self._components): |
| 249 | + return self._components[pos] |
| 250 | + msg = '{.__name__!r} object has no attribute {!r}' |
| 251 | + raise AttributeError(msg.format(cls, name)) |
| 252 | + |
| 253 | + def angle(self): |
| 254 | + return math.atan2(self.y, self.x) # <1> |
| 255 | + |
| 256 | + def __format__(self, fmt_spec=''): |
| 257 | + if fmt_spec.endswith('p'): |
| 258 | + fmt_spec = fmt_spec[:-1] |
| 259 | + coords = (abs(self), self.angle()) |
| 260 | + outer_fmt = '<{}>' # <2> |
| 261 | + else: |
| 262 | + coords = self |
| 263 | + outer_fmt = '({})' # <3> |
| 264 | + components = (format(c, fmt_spec) for c in coords) |
| 265 | + return outer_fmt.format(', '.join(components)) # <4> |
| 266 | + |
| 267 | + @classmethod |
| 268 | + def frombytes(cls, octets): |
| 269 | + memv = memoryview(octets).cast(cls.typecode) |
| 270 | + return cls(memv) |
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