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coach/memories/differentiable_neural_dictionary.py
Roman Dobosz 1b095aeeca Cleanup imports.
Till now, most of the modules were importing all of the module objects
(variables, classes, functions, other imports) into module namespace,
which potentially could (and was) cause of unintentional use of class or
methods, which was indirect imported.

With this patch, all the star imports were substituted with top-level
module, which provides desired class or function.

Besides, all imports where sorted (where possible) in a way pep8[1]
suggests - first are imports from standard library, than goes third
party imports (like numpy, tensorflow etc) and finally coach modules.
All of those sections are separated by one empty line.

[1] https://www.python.org/dev/peps/pep-0008/#imports
2018-04-13 09:58:40 +02:00

208 lines
7.5 KiB
Python

#
# Copyright (c) 2017 Intel Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import os
import pickle
import numpy as np
from annoy import AnnoyIndex
class AnnoyDictionary(object):
def __init__(self, dict_size, key_width, new_value_shift_coefficient=0.1, batch_size=100, key_error_threshold=0.01):
self.max_size = dict_size
self.curr_size = 0
self.new_value_shift_coefficient = new_value_shift_coefficient
self.index = AnnoyIndex(key_width, metric='euclidean')
self.index.set_seed(1)
self.embeddings = np.zeros((dict_size, key_width))
self.values = np.zeros(dict_size)
self.lru_timestamps = np.zeros(dict_size)
self.current_timestamp = 0.0
# keys that are in this distance will be considered as the same key
self.key_error_threshold = key_error_threshold
self.initial_update_size = batch_size
self.min_update_size = self.initial_update_size
self.key_dimension = key_width
self.value_dimension = 1
self._reset_buffer()
self.built_capacity = 0
def add(self, keys, values):
# Adds new embeddings and values to the dictionary
indices = []
indices_to_remove = []
for i in range(keys.shape[0]):
index = self._lookup_key_index(keys[i])
if index:
# update existing value
self.values[index] += self.new_value_shift_coefficient * (values[i] - self.values[index])
self.lru_timestamps[index] = self.current_timestamp
indices_to_remove.append(i)
else:
# add new
if self.curr_size >= self.max_size:
# find the LRU entry
index = np.argmin(self.lru_timestamps)
else:
index = self.curr_size
self.curr_size += 1
self.lru_timestamps[index] = self.current_timestamp
indices.append(index)
for i in reversed(indices_to_remove):
keys = np.delete(keys, i, 0)
values = np.delete(values, i, 0)
self.buffered_keys = np.vstack((self.buffered_keys, keys))
self.buffered_values = np.vstack((self.buffered_values, values))
self.buffered_indices = self.buffered_indices + indices
if len(self.buffered_indices) >= self.min_update_size:
self.min_update_size = max(self.initial_update_size, int(self.curr_size * 0.02))
self._rebuild_index()
self.current_timestamp += 1
# Returns the stored embeddings and values of the closest embeddings
def query(self, keys, k):
if not self.has_enough_entries(k):
# this will only happen when the DND is not yet populated with enough entries, which is only during heatup
# these values won't be used and therefore they are meaningless
return [0.0], [0.0], [0]
_, indices = self._get_k_nearest_neighbors_indices(keys, k)
embeddings = []
values = []
for ind in indices:
self.lru_timestamps[ind] = self.current_timestamp
embeddings.append(self.embeddings[ind])
values.append(self.values[ind])
self.current_timestamp += 1
return embeddings, values, indices
def has_enough_entries(self, k):
return self.curr_size > k and (self.built_capacity > k)
def _get_k_nearest_neighbors_indices(self, keys, k):
distances = []
indices = []
for key in keys:
index, distance = self.index.get_nns_by_vector(key, k, include_distances=True)
distances.append(distance)
indices.append(index)
return distances, indices
def _rebuild_index(self):
self.index.unbuild()
self.embeddings[self.buffered_indices] = self.buffered_keys
self.values[self.buffered_indices] = np.squeeze(self.buffered_values)
for idx, key in zip(self.buffered_indices, self.buffered_keys):
self.index.add_item(idx, key)
self._reset_buffer()
self.index.build(50)
self.built_capacity = self.curr_size
def _reset_buffer(self):
self.buffered_keys = np.zeros((0, self.key_dimension))
self.buffered_values = np.zeros((0, self.value_dimension))
self.buffered_indices = []
def _lookup_key_index(self, key):
distance, index = self._get_k_nearest_neighbors_indices([key], 1)
if distance != [[]] and distance[0][0] <= self.key_error_threshold:
return index
return None
class QDND:
def __init__(self, dict_size, key_width, num_actions, new_value_shift_coefficient=0.1, key_error_threshold=0.01,
learning_rate=0.01):
self.num_actions = num_actions
self.dicts = []
self.learning_rate = learning_rate
# create a dict for each action
for a in range(num_actions):
new_dict = AnnoyDictionary(dict_size, key_width, new_value_shift_coefficient, key_error_threshold=key_error_threshold)
self.dicts.append(new_dict)
def add(self, embeddings, actions, values):
# add a new set of embeddings and values to each of the underlining dictionaries
embeddings = np.array(embeddings)
actions = np.array(actions)
values = np.array(values)
for a in range(self.num_actions):
idx = np.where(actions == a)
curr_action_embeddings = embeddings[idx]
curr_action_values = np.expand_dims(values[idx], -1)
self.dicts[a].add(curr_action_embeddings, curr_action_values)
return True
def query(self, embeddings, action, k):
# query for nearest neighbors to the given embeddings
dnd_embeddings = []
dnd_values = []
dnd_indices = []
for i in range(len(embeddings)):
embedding, value, indices = self.dicts[action].query([embeddings[i]], k)
dnd_embeddings.append(embedding[0])
dnd_values.append(value[0])
dnd_indices.append(indices[0])
return dnd_embeddings, dnd_values, dnd_indices
def has_enough_entries(self, k):
# check if each of the action dictionaries has at least k entries
for a in range(self.num_actions):
if not self.dicts[a].has_enough_entries(k):
return False
return True
def load_dnd(model_dir):
max_id = 0
for f in [s for s in os.listdir(model_dir) if s.endswith('.dnd')]:
if int(f.split('.')[0]) > max_id:
max_id = int(f.split('.')[0])
model_path = str(max_id) + '.dnd'
with open(os.path.join(model_dir, model_path), 'rb') as f:
DND = pickle.load(f)
for a in range(DND.num_actions):
DND.dicts[a].index = AnnoyIndex(512, metric='euclidean')
DND.dicts[a].index.set_seed(1)
for idx, key in zip(range(DND.dicts[a].curr_size), DND.dicts[a].embeddings[:DND.dicts[a].curr_size]):
DND.dicts[a].index.add_item(idx, key)
DND.dicts[a].index.build(50)
return DND