def testinit(self):
n = 15
P = [R1(i) for i in range(n)]
M = MetricSpace(P)
for j in range(n):
for i in range(n - j):
self.assertEqual(M.dist(P[i], P[i + j]), j)
def test_dist_and_distsq(self):
class TestPoint(float):
def dist(self, other):
return 2 * abs(self - other)
a = TestPoint(4)
b = TestPoint(5)
c = TestPoint(9)
M = MetricSpace([a, b, c])
self.assertEqual(M.dist(a, b), 2)
self.assertEqual(M.dist(a, c), 10)
self.assertEqual(M.dist(c, a), 10)
self.assertEqual(M.dist(a, b), 2) # still
self.assertEqual(M.dist(c, b), 8)
self.assertEqual(M.distsq(a, b), 4)
self.assertEqual(M.distsq(a, c), 100)
self.assertEqual(M.distsq(c, a), 100)
self.assertEqual(M.distsq(a, b), 4) # still
self.assertEqual(M.distsq(c, b), 64)
def testcaching(self):
class TestPoint:
def __init__(self):
self.distances_computed = set()
def dist(self, other):
assert ((self, other) not in self.distances_computed)
self.distances_computed.add((self, other))
return 0
a, b, c = TestPoint(), TestPoint(), TestPoint()
M = MetricSpace([a, b])
self.assertEqual(M.dist(a, b), 0)
with self.assertRaises(AssertionError):
a.dist(b)
# Reversing operands also hits the cache.
self.assertEqual(M.dist(b, a), 0)
# Other distances can still be computed.
self.assertEqual(a.dist(c), 0)
self.assertEqual(b.dist(c), 0)
