def _known_unit(
self,
hash_ftor: LshFunctor,
hash_idx: Optional[HashIndex],
dist_method: str,
ftor_train_hook: Callable[[Iterable[DescriptorElement]],
None] = lambda d: None
) -> None:
###
# Unit vectors - Equal distance
#
dim = 5
test_descriptors = []
for i in range(dim):
v = np.zeros(dim, float)
v[i] = 1.
test_descriptors.append(
DescriptorMemoryElement('unit', i).set_vector(v))
ftor_train_hook(test_descriptors)
di = MemoryDescriptorSet()
kvstore = MemoryKeyValueStore()
index = LSHNearestNeighborIndex(hash_ftor,
di,
kvstore,
hash_index=hash_idx,
distance_method=dist_method)
index.build_index(test_descriptors)
# query with zero vector
# -> all modeled descriptors have no intersection, dists should be 1.0,
# or maximum distance by histogram intersection
q = DescriptorMemoryElement('query', 0)
q.set_vector(np.zeros(dim, float))
r, dists = index.nn(q, dim)
# All dists should be 1.0, r order doesn't matter
for d in dists:
self.assertEqual(d, 1.)
# query with index element
q = test_descriptors[3]
r, dists = index.nn(q, 1)
self.assertEqual(r[0], q)
self.assertEqual(dists[0], 0.)
r, dists = index.nn(q, dim)
self.assertEqual(r[0], q)
self.assertEqual(dists[0], 0.)
def _known_ordered_euclidean(
self,
hash_ftor: LshFunctor,
hash_idx: Optional[HashIndex],
ftor_train_hook: Callable[[Iterable[DescriptorElement]],
None] = lambda d: None
) -> None:
# make vectors to return in a known euclidean distance order
i = 1000
test_descriptors = [
DescriptorMemoryElement('ordered',
j).set_vector(np.array([j, j * 2], float))
for j in range(i)
]
random.shuffle(test_descriptors)
ftor_train_hook(test_descriptors)
di = MemoryDescriptorSet()
kvstore = MemoryKeyValueStore()
index = LSHNearestNeighborIndex(hash_ftor,
di,
kvstore,
hash_index=hash_idx,
distance_method='euclidean')
index.build_index(test_descriptors)
# Since descriptors were built in increasing distance from (0,0),
# returned descriptors for a query of [0,0] should be in index order.
q = DescriptorMemoryElement('query', i)
q.set_vector(np.array([0, 0], float))
# top result should have UUID == 0 (nearest to query)
r, dists = index.nn(q, 5)
self.assertEqual(r[0].uuid(), 0)
self.assertEqual(r[1].uuid(), 1)
self.assertEqual(r[2].uuid(), 2)
self.assertEqual(r[3].uuid(), 3)
self.assertEqual(r[4].uuid(), 4)
# global search should be in complete order
r, dists = index.nn(q, i)
for j, d, dist in zip(range(i), r, dists):
self.assertEqual(d.uuid(), j)
def _random_euclidean(
self,
hash_ftor: LshFunctor,
hash_idx: Optional[HashIndex],
ftor_train_hook: Callable[[Iterable[DescriptorElement]],
None] = lambda d: None
) -> None:
# :param hash_ftor: Hash function class for generating hash codes for
# descriptors.
# :param hash_idx: Hash index instance to use in local LSH algo
# instance.
# :param ftor_train_hook: Function for training functor if necessary.
# make random descriptors
i = 1000
dim = 256
td = []
np.random.seed(self.RANDOM_SEED)
for j in range(i):
d = DescriptorMemoryElement('random', j)
d.set_vector(np.random.rand(dim))
td.append(d)
ftor_train_hook(td)
di = MemoryDescriptorSet()
kvstore = MemoryKeyValueStore()
index = LSHNearestNeighborIndex(hash_ftor,
di,
kvstore,
hash_index=hash_idx,
distance_method='euclidean')
index.build_index(td)
# test query from build set -- should return same descriptor when k=1
q = td[255]
r, dists = index.nn(q, 1)
self.assertEqual(r[0], q)
# test query very near a build vector
td_q = td[0]
q = DescriptorMemoryElement('query', i)
td_q_v = td_q.vector()
assert td_q_v is not None
v = td_q_v.copy()
v_min = max(v.min(), 0.1)
v[0] += v_min
v[dim - 1] -= v_min
q.set_vector(v)
r, dists = index.nn(q, 1)
self.assertFalse(np.array_equal(q.vector(), td_q.vector()))
self.assertEqual(r[0], td_q)
# random query
q = DescriptorMemoryElement('query', i + 1)
q.set_vector(np.random.rand(dim))
# for any query of size k, results should at least be in distance order
r, dists = index.nn(q, 10)
for j in range(1, len(dists)):
self.assertGreater(dists[j], dists[j - 1])
r, dists = index.nn(q, i)
for j in range(1, len(dists)):
self.assertGreater(dists[j], dists[j - 1])
