annoy (precision) with examples#
An example showing the annoy function.
# Authors: Spotify AB
# SPDX-License-Identifier: Apache-2.0
from __future__ import print_function
import random, time
# from annoy import AnnoyIndex
from scikitplot.cexternals.annoy import AnnoyIndex
try:
xrange
except NameError:
# Python 3 compat
xrange = range
n, f = 100000, 40
t = AnnoyIndex(f, 'angular')
for i in xrange(n):
v = []
for z in xrange(f):
v.append(random.gauss(0, 1))
t.add_item(i, v)
t.build(2 * f)
t.save('test.tree')
limits = [10, 100, 1000, 10000]
k = 10
prec_sum = {}
prec_n = 1000
time_sum = {}
for i in xrange(prec_n):
j = random.randrange(0, n)
closest = set(t.get_nns_by_item(j, k, n))
for limit in limits:
t0 = time.time()
toplist = t.get_nns_by_item(j, k, limit)
T = time.time() - t0
found = len(closest.intersection(toplist))
hitrate = 1.0 * found / k
prec_sum[limit] = prec_sum.get(limit, 0.0) + hitrate
time_sum[limit] = time_sum.get(limit, 0.0) + T
for limit in limits:
print('limit: %-9d precision: %6.2f%% avg time: %.6fs'
% (limit, 100.0 * prec_sum[limit] / (i + 1),
time_sum[limit] / (i + 1)))
limit: 10 precision: 13.36% avg time: 0.000066s
limit: 100 precision: 20.27% avg time: 0.000066s
limit: 1000 precision: 56.22% avg time: 0.000245s
limit: 10000 precision: 96.94% avg time: 0.001643s
Total running time of the script: (0 minutes 21.742 seconds)
Related examples
