# /usr/bin/env python3.6
# -*- mode: python -*-
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"""BatchNorm Re-estimation"""
from typing import List, Tuple, Dict
import numpy as np
import tensorflow as tf
from aimet_common.utils import Handle, AimetLogger
from aimet_tensorflow.utils.op.fusedbatchnorm import BNUtils
from aimet_tensorflow.common.graph_eval import initialize_uninitialized_vars
from aimet_tensorflow.quantsim import QuantizationSimModel
from aimet_tensorflow.utils.common import create_input_feed_dict, iterate_tf_dataset
from aimet_tensorflow.utils.op.bn_mutable import get_active_bn_ops
logger = AimetLogger.get_area_logger(AimetLogger.LogAreas.Quant)
# pylint: disable=too-many-locals
def _get_all_tf_bn_vars_list(sim: QuantizationSimModel) -> Tuple[List[tf.Variable],
List[tf.Variable],
List[tf.Variable],
List[tf.Variable]]:
"""
find tf variables list to access BNs mean, variance, momentum and is_training
:param sim: tf quantized model
:return: tf.variable lists to access bn layers's mean, var, momentum, is_training
"""
conn_graph = sim.connected_graph
bn_conn_graph_ops = tuple(get_active_bn_ops(conn_graph))
with sim.session.graph.as_default():
tf_global_vars = tf.compat.v1.get_collection(tf.compat.v1.GraphKeys.GLOBAL_VARIABLES)
mean_tf_var_names = []
variance_tf_var_names = []
is_training_tf_var_names = []
momentum_tf_var_names = []
for bn_conn_graph_op in bn_conn_graph_ops:
tf_op = bn_conn_graph_op.internal_ops[0]
assert tf_op.type in ['Identity'], 'Fused Batch Norm with training tensor is only supported.'
bn_mean_tf_var_name = tf_op.inputs[0].op.inputs[3].name
bn_var_tf_var_name = tf_op.inputs[0].op.inputs[4].name
bn_cond_1_tf_op = BNUtils.get_cond_1_identity_op(tf_op)
bn_momentum_tf_var_name = bn_cond_1_tf_op.inputs[0].op.inputs[1].name
bn_training_tf_var_name = tf_op.inputs[0].op.inputs[0].op.inputs[0].name
mean_tf_var_names.append(bn_mean_tf_var_name)
variance_tf_var_names.append(bn_var_tf_var_name)
momentum_tf_var_names.append(bn_momentum_tf_var_name)
is_training_tf_var_names.append(bn_training_tf_var_name)
mean_tf_vars = []
variance_tf_vars = []
is_training_tf_vars = []
momentum_tf_vars = []
for v in tf_global_vars:
if v.name in mean_tf_var_names:
mean_tf_vars.append(v)
if v.name in variance_tf_var_names:
variance_tf_vars.append(v)
if v.name in momentum_tf_var_names:
momentum_tf_vars.append(v)
if v.name in is_training_tf_var_names:
is_training_tf_vars.append(v)
return mean_tf_vars, variance_tf_vars, momentum_tf_vars, is_training_tf_vars
def _reset_bn_stats(sess: tf.compat.v1.Session,
bn_mean_checkpoints: Dict[tf.Variable, np.ndarray],
bn_variance_checkpoints: Dict[tf.Variable, np.ndarray]) -> Handle:
"""
Reset all BNs statistics to the initial values.
:param sess: tf session
:param bn_mean_checkpoints: Dict for original BN mean
:param bn_variance_checkpoints: Dict for original BN variance
:return: Handle that restores the original BN statistics upon handle.remove().
"""
def cleanup():
"""
Restore all BNs stats
"""
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(v, bn_mean_checkpoints[v]) for v in bn_mean_checkpoints])
sess.run([tf.compat.v1.assign(v, bn_variance_checkpoints[v]) for v in bn_variance_checkpoints])
try:
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(v, np.zeros(v.shape, dtype=v.dtype.as_numpy_dtype))
for v in bn_mean_checkpoints])
sess.run([tf.compat.v1.assign(v, np.ones(v.shape, dtype=v.dtype.as_numpy_dtype))
for v in bn_variance_checkpoints])
return Handle(cleanup)
except:
cleanup()
raise
def _reset_momentum(sess: tf.compat.v1.Session,
momentum_checkpoints: Dict[tf.Variable, np.float32]) -> Handle:
"""
Set all BNs momentum to 0.0.
:param sess: tf session
:param momentum_checkpoints: Dict for original BN momentum[tf.Variable --> original_values]
:return: Handle that restores the original BN statistics upon handle.remove().
"""
def cleanup():
"""
Restore BNs momentum
"""
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(v, momentum_checkpoints[v]) for v in momentum_checkpoints])
try:
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(v, 0.0) for v in momentum_checkpoints])
return Handle(cleanup)
except:
cleanup()
raise
def _set_bn_in_train_mode(sess: tf.compat.v1.Session,
is_training_checkpoints: Dict[tf.Variable, bool]) -> Handle:
"""
Set BNs in training mode.
:param sess: tf session
:param is_training_checkpoints: Dict for original BNs is_training flag.
:return: Handle that sets all mutable BNs to eval mode upon handle.remove().
"""
def cleanup():
"""
Set all the BNs to eval mode.
"""
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(k, False) for k in is_training_checkpoints])
try:
# Set all the BNs to train mode
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(k, True) for k in is_training_checkpoints])
return Handle(cleanup)
except:
cleanup()
raise
def _get_tf_vars_and_orig_values(sim: QuantizationSimModel) -> Tuple[Dict[tf.Variable, np.ndarray],
Dict[tf.Variable, np.ndarray],
Dict[tf.Variable, np.float32],
Dict[tf.Variable, bool]]:
"""
save original values for all BNs mean, variance, momentum and is_training tf Variables.
:param sim: QuantizationSimModel object.
:return: Dictionary [tf.Variable] --> original_value for all BNs mean, variance, momentum and is_training.
"""
# setup tf variable list to access
mean_tf_vars, variance_tf_vars, momentum_tf_vars, is_training_tf_vars = _get_all_tf_bn_vars_list(sim)
with sim.session.graph.as_default():
mean_checkpoints = dict(zip(mean_tf_vars, sim.session.run([v for v in mean_tf_vars])))
variance_checkpoints = dict(zip(variance_tf_vars, sim.session.run([v for v in variance_tf_vars])))
momentum_checkpoints = dict(zip(momentum_tf_vars, sim.session.run([v for v in momentum_tf_vars])))
is_training_checkpoints = dict(zip(is_training_tf_vars, sim.session.run([v for v in is_training_tf_vars])))
return mean_checkpoints, variance_checkpoints, momentum_checkpoints, is_training_checkpoints
DEFAULT_NUM_BATCHES = 100
[docs]def reestimate_bn_stats(sim: QuantizationSimModel,
start_op_names: List[str],
output_op_names: List[str],
dataset: tf.compat.v1.data.Dataset,
num_batches: int = DEFAULT_NUM_BATCHES) -> Handle:
"""
Reestimate BatchNorm statistics (running mean and var).
:param sim: QuantizationSimModel object.
:param start_op_names: List of starting op names of the model
:param output_op_names: List of output op names of the model
:param dataset: Training dataset
:param num_batches: The number of batches to be used for reestimation
:returns: Handle that undos the effect of BN reestimation upon handle.remove()
"""
# setup tf variable list to access
mean_checkpoints, variance_checkpoints, momentum_checkpoints, is_training_checkpoints = \
_get_tf_vars_and_orig_values(sim)
sess = sim.session
# Set all the BNs in training mode
with _set_bn_in_train_mode(sess, is_training_checkpoints), _reset_momentum(sess, momentum_checkpoints):
handle = _reset_bn_stats(sess, mean_checkpoints, variance_checkpoints)
try:
with sess.graph.as_default():
output_tensors = [sess.graph.get_tensor_by_name(name + ':0') for name in output_op_names]
update_ops = tf.compat.v1.get_collection(tf.compat.v1.GraphKeys.UPDATE_OPS)
assert update_ops, "GraphKeys.UPDATE_OPS can not be empty."
# GraphKeys.UPDATE_OPS is collection of moving mean and variance for BN layers. During training mode
# moving mean and variance need to be updated and added as a control dependency.
with tf.compat.v1.control_dependencies(update_ops):
output_tensors_dependencies = []
for output_tensor in output_tensors:
output_tensor = tf.compat.v1.identity(output_tensor)
output_tensors_dependencies.append(output_tensor)
initialize_uninitialized_vars(sess)
# BN statistics accumulation buffer
sum_mean = {v: np.zeros(v.shape, dtype=v.dtype.as_numpy_dtype) for v in mean_checkpoints}
sum_var = {v: np.zeros(v.shape, dtype=v.dtype.as_numpy_dtype) for v in variance_checkpoints}
batches = 0
iterator = iterate_tf_dataset(dataset)
for _ in range(num_batches):
try:
data = next(iterator)
batches += 1
except StopIteration:
break
feed_dict = create_input_feed_dict(sess.graph, start_op_names, data)
sess.run(output_tensors_dependencies, feed_dict=feed_dict)
for v in mean_checkpoints:
sum_mean[v] += sess.run(v)
for v in variance_checkpoints:
sum_var[v] += sess.run(v)
# Override BN stats with the reestimated stats.
with sess.graph.as_default():
sess.run([tf.compat.v1.assign(v, sum_mean[v] / batches) for v in mean_checkpoints])
sess.run([tf.compat.v1.assign(v, sum_var[v] / batches) for v in variance_checkpoints])
return handle
except:
handle.remove()
raise