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 greedyHD(A: MetricSpace, B: MetricSpace):
"""
Compute Hausdorff distance after taking greedy permutations of A and B.
"""
A_g = MetricSpace(points = list(greedy(A)), dist = A.distfn, cache = A.cache, turnoffcache = A.turnoffcache)
B_g = MetricSpace(points = list(greedy(B)), dist = B.distfn, cache = B.cache, turnoffcache = B.turnoffcache)
return naiveHD(A_g, B_g)
def testinit_with_center(self):
M = MetricSpace([Point([2 * i, 2 * i]) for i in range(100)])
MetricCell = Cell(MetricSpace())
C = MetricCell(Point([99, 99]))
for p in M:
C.addpoint(p)
self.assertEqual(len(C), 101)
def testiter(self):
"""
The iteration order should match the insertion order.
"""
P = [R1(5), R1(2), R1(3)]
M = MetricSpace(P)
self.assertEqual(P, list(M))
newpoint = R1(4)
M.add(newpoint)
self.assertEqual(P + [R1(4)], list(M))
def testrebalance(self):
a, b = Point([-1]), Point([200])
G = NeighborGraph(MetricSpace([a, b]))
MetricCell = Cell(MetricSpace())
A = MetricCell(a)
B = MetricCell(b)
for i in range(200):
B.addpoint(Point([i]))
self.assertEqual(len(A), 1)
self.assertEqual(len(B), 201)
G.rebalance(A, B)
self.assertEqual(len(B), 101)
self.assertEqual(len(A), 101)
def test_points_on_a_line():
P = [Point([i]) for i in range(100)]
GP = list(onehopgreedy(MetricSpace(P), P[50]))
assert(GP[0] == P[50])
expected = [50, 16, 83]
n = len(expected)
assert(GP[:n] == [P[i] for i in expected])
def testgreedytree_transportplan_mass(self):
"""
This test determines that greedy() computes the correct transportation plan
"""
greedy = self.implementation.greedy
root = Point([0])
P = MetricSpace([root] + [Point([x]) for x in [9, 3, 5, 18]])
#gp = greedy(P, root, tree=False, gettransportplan = True)
gp = greedy(P,
root,
tree=False,
gettransportplan=True,
mass=[2, 2, 2, 2, 2])
# A case-wise assertion was needed because the way clarksongreedy.greedy works,
# it looks into all neighbors which might have been changed when a new cell was
# created. So the transportation plan has entries in the dictionary with 0 mass
# moved. On the other hand quadraticgreedy.greedy stores points in the
# transportation plan only if their reverse nearest neighbor changed.
# So there are no 0 value keys here.
if self.implementation == clarksongreedy:
self.assertEqual(next(gp), (Point([0]), {Point([0]): 10}))
self.assertEqual(next(gp), (Point([18]), {
Point([0]): -2,
Point([18]): 2
}))
self.assertEqual(next(gp), (Point([9]), {
Point([9]): 4,
Point([0]): -4,
Point([18]): 0
}))
self.assertEqual(next(gp), (Point([5]), {
Point([9]): -2,
Point([0]): -2,
Point([5]): 4
}))
self.assertEqual(next(gp), (Point([3]), {
Point([9]): 0,
Point([3]): 2,
Point([5]): -2
}))
else:
self.assertEqual(next(gp), (Point([0]), {Point([0]): 10}))
self.assertEqual(next(gp), (Point([18]), {
Point([0]): -2,
Point([18]): 2
}))
self.assertEqual(next(gp), (Point([9]), {
Point([9]): 4,
Point([0]): -4
}))
self.assertEqual(next(gp), (Point([5]), {
Point([9]): -2,
Point([0]): -2,
Point([5]): 4
}))
self.assertEqual(next(gp), (Point([3]), {
Point([3]): 2,
Point([5]): -2
}))
def test_smallinstance(self):
k = 11
# S = set(range(0, 100, 4))
S = set(range(0, 100, 4)) | set(range(100, 200, 10))
P = [Point([c]) for c in S]
M = MetricSpace(P)
output = list(knnsample(M, k, P[0]))
print(len(output), output)
self.assertTrue(len(output) >= len(S) / k)
def testgreedy_exponential_example(self):
greedy = self.implementation.greedy
P = [Point([(-3)**i]) for i in range(100)]
# print([str(p) for p in P])
M = MetricSpace(P)
gp = greedy(M, P[0])
self.assertEqual(next(gp), P[0])
self.assertEqual(next(gp), P[99])
for i in range(98, 0, -1):
self.assertEqual(next(gp), P[i])
def testaddpoint(self):
a, b, c = Point([1, 2]), Point([2, 3]), Point([3, 4])
MetricCell = Cell(MetricSpace())
C = MetricCell(a)
self.assertEqual(len(C), 1)
C.addpoint(b)
self.assertEqual(len(C), 2)
C.addpoint(c)
self.assertEqual(len(C), 3)
self.assertEqual(C.points, {a, b, c})
def test_getitem_subspace(self):
def dist(x: float, y: float):
return abs(x - y)
a = 1
b = 5
c = 9
M = MetricSpace([a, b, c], dist)
self.assertEqual(M[0], 1)
M_1 = M[1:]
self.assertEqual(M_1.dist(M_1[0], M_1[1]), 4)
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)
def testgreedytree_example2(self):
greedy = self.implementation.greedy
P = [Point([c]) for c in [0, 100, 49, 25, 60, 12, 81]]
M = MetricSpace(P)
root = P[0]
gt = list(greedy(M, root, tree=True))
gp = [p for p, i in gt]
ch = defaultdict(list)
for p, i in greedy(M, root, tree=True):
if i is not None:
ch[gp[i]].append(p)
self.assertEqual(gp, [P[i] for i in [0, 1, 2, 3, 6, 5, 4]])
def testpop(self):
a, b, c, d = Point([0, 0]), Point([100,
0]), Point([0, 50]), Point([25, 25])
MetricCell = Cell(MetricSpace())
C = MetricCell(a)
C.addpoint(b)
C.addpoint(c)
C.addpoint(d)
self.assertEqual(C.pop(), b)
self.assertEqual(C.pop(), c)
self.assertEqual(C.pop(), d)
self.assertEqual(C.pop(), None)
def testgreedytree_randomexample(self):
greedy = self.implementation.greedy
root = Point([0])
P = MetricSpace([root] +
[Point([x]) for x in [8, 12, 100, 40, 70, 1, 72]])
gp = greedy(P, root, tree=True)
self.assertEqual(next(gp), (Point([0]), None))
self.assertEqual(next(gp), (Point([100]), 0)) # radius = 100
self.assertEqual(next(gp), (Point([40]), 0))
self.assertEqual(next(gp), (Point([70]), 1))
self.assertEqual(next(gp), (Point([12]), 0))
self.assertEqual(next(gp), (Point([8]), 4))
self.assertEqual(next(gp), (Point([72]), 3))
def testaddpoint_duplicatepoint(self):
a, b = Point([1, 2]), Point([2, 3])
MetricCell = Cell(MetricSpace())
C = MetricCell(a)
self.assertEqual(len(C), 1)
C.addpoint(b)
self.assertEqual(len(C), 2)
# Add b a second time.
C.addpoint(b)
self.assertEqual(len(C), 2)
self.assertEqual(C.points, {a, b})
# Add the center again.
C.addpoint(a)
self.assertEqual(len(C), 2)
self.assertEqual(C.points, {a, b})
def testgreedytree_bigexample(self):
greedy = self.implementation.greedy
n = 600
coords = set()
while len(coords) < n:
coords.add((randrange(100), randrange(100), randrange(100)))
P = [Point(c) for c in coords]
M = MetricSpace(P)
GP = list(greedy(M, P[0], tree=True))
radii = [p.dist(GP[i][0]) for p, i in GP if i is not None]
# Check that the insertion radii are nonincreasing.
for i in range(n - 2):
self.assertTrue(radii[i] >= radii[i + 1],
str([i, radii[i], radii[i + 1]]))
def naiveDirectedHD(A: MetricSpace, B: MetricSpace, cmax: float = 0):
"""
Compute directed Hausdorff distance naively in O(n^2) time.
"""
for a in A:
cmin = float('inf')
cont = True
for b in B:
d = A.distfn(a,b)
if d < cmax:
cont = False
break
if d < cmin:
cmin = d
if cont and cmin > cmax:
cmax = cmin
return cmax
def testgreedytree_example3(self):
greedy = self.implementation.greedy
P = [Point([c]) for c in [0, 1, 3, 5, 20, 30]]
M = MetricSpace(P)
gt = list(greedy(M, P[0], tree=True))
gp = [p for p, i in gt]
ch = defaultdict(set)
for p, i in gt:
if i is not None:
ch[gp[i]].add(p)
self.assertEqual(gp, [P[0], P[5], P[4], P[3], P[2], P[1]])
self.assertEqual(ch[P[0]], {P[5], P[3], P[1]})
self.assertEqual(ch[P[1]], set())
self.assertEqual(ch[P[2]], set())
self.assertEqual(ch[P[3]], {P[2]})
self.assertEqual(ch[P[4]], set())
self.assertEqual(ch[P[5]], {P[4]})
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 testneighborsofneighborscondition(self):
""" This somewhat long test was written to expose a bug where
neighbors of the neighbor graph were not properly discovered.
The construction highlights the need for the neighbor graph to be
undirected.
"""
a = L_inf([0, 2, 21, 11, 22, 19])
aa = L_inf([2, 0, 19, 9, 20, 17])
b = L_inf([21, 19, 0, 10, 21, 18])
bb = L_inf([11, 9, 10, 0, 11, 8])
c = L_inf([22, 20, 21, 11, 0, 3])
cc = L_inf([19, 17, 18, 8, 3, 0])
P = [a, aa, b, bb, c, cc]
G = NeighborGraph(MetricSpace(P))
self.assertEqual(len(G), 1)
p = G.heap.findmax()
self.assertEqual(p.center, a)
self.assertEqual(p.pop(), c)
G.addcell(c, p)
self.assertEqual(len(G), 2)
p = G.heap.findmax()
self.assertEqual(p.pop(), b)
G.addcell(b, p)
V = {v.center: v for v in G.vertices()}
self.assertEqual(set(V), {a, b, c})
self.assertTrue(V[b] in G.nbrs(V[a]))
self.assertTrue(V[a] in G.nbrs(V[b]))
self.assertTrue(V[b] in G.nbrs(V[c]))
self.assertTrue(V[c] in G.nbrs(V[b]))
# Before adding aa.
self.assertTrue(bb in V[b])
self.assertEqual(V[a].pop(), aa)
G.addcell(aa, V[a])
V = {v.center: v for v in G.vertices()}
# After adding aa.
self.assertTrue(cc in V[c])
self.assertTrue(bb in V[aa])
self.assertTrue(bb.dist(cc) < bb.dist(aa))
# That means that we should have an edge from c to aa.
self.assertTrue(V[aa] in G.nbrs(V[c]))
def testdist(self):
MetricCell = Cell(MetricSpace())
A = MetricCell(Point([2, 3]))
self.assertEqual(A.dist(Point([7, 3])), 5)
self.assertEqual(A.dist(A.center), 0)
self.assertEqual(A.dist(Point([7, 15])), 13)
def testupdateradius_empty_cell(self):
MetricCell = Cell(MetricSpace())
C = MetricCell(Point([1, 2, 3]))
C.updateradius()
self.assertEqual(C.radius, 0)
def naiveHD(A: MetricSpace, B: MetricSpace, cmax: float = 0):
"""
Compute the Hausdorff distance naively using 2 calls to naiveDirectedHD
"""
return max(naiveDirectedHD(A, B, cmax), naiveDirectedHD(B, A, cmax))
def greedyHD(A: MetricSpace, B: MetricSpace):
"""
Compute Hausdorff distance after taking greedy permutations of A and B.
"""
A_g = MetricSpace(points = list(greedy(A)), dist = A.distfn, cache = A.cache, turnoffcache = A.turnoffcache)
B_g = MetricSpace(points = list(greedy(B)), dist = B.distfn, cache = B.cache, turnoffcache = B.turnoffcache)
return naiveHD(A_g, B_g)
def l_inf(p: Point, q: Point):
return max(abs(p[0] - q[0]), abs(p[1] - q[1]))
M = 300
N = 350
seed(0)
points = [Point([randrange(5, M-5), randrange(5,M-5)]) for i in range(N)]
points = list(dict.fromkeys(points))
X = MetricSpace(points = points, dist=l_inf)
A = X[:N//2]
B = X[N//2:]
print(naiveHD(A, B))
print(greedyHD(A, B))
def testinit(self):
n = 9
P = [Point((i, 0, j, 0)) for i in range(n) for j in range(n)]
M = MetricSpace(P)
MDS(M)
def setUp(self):
self.P = [Point([c]) for c in [0, 100, 49, 25, 60, 12, 81]]
self.M = MetricSpace(self.P)
def testinit_empty(self):
M = MetricSpace()
def testbasicusage(self):
G = NeighborGraph(MetricSpace([Point([i, i]) for i in range(100)]))
def metricspace(self, target_dimension=False):
n = len(self.M)
return MetricSpace([NumpyPoint(self.Q[i]) for i in range(n)])
def testgreedy(self):
greedy = self.implementation.greedy
P = [Point([i]) for i in range(3)]
M = MetricSpace(P)
gp = list(greedy(M, P[0]))
self.assertEqual(gp, [P[0], P[2], P[1]])