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# Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
#
# NVIDIA CORPORATION and its licensors retain all intellectual property
# and proprietary rights in and to this software, related documentation
# and any modifications thereto. Any use, reproduction, disclosure or
# distribution of this software and related documentation without an express
# license agreement from NVIDIA CORPORATION is strictly prohibited.
"""Miscellaneous helper utils for Tensorflow."""
import os
import numpy as np
import tensorflow as tf
# Silence deprecation warnings from TensorFlow 1.13 onwards
import logging
logging.getLogger('tensorflow').setLevel(logging.ERROR)
import tensorflow.contrib # requires TensorFlow 1.x!
tf.contrib = tensorflow.contrib
from typing import Any, Iterable, List, Union
TfExpression = Union[tf.Tensor, tf.Variable, tf.Operation]
"""A type that represents a valid Tensorflow expression."""
TfExpressionEx = Union[TfExpression, int, float, np.ndarray]
"""A type that can be converted to a valid Tensorflow expression."""
def run(*args, **kwargs) -> Any:
"""Run the specified ops in the default session."""
assert_tf_initialized()
return tf.get_default_session().run(*args, **kwargs)
def is_tf_expression(x: Any) -> bool:
"""Check whether the input is a valid Tensorflow expression, i.e., Tensorflow Tensor, Variable, or Operation."""
return isinstance(x, (tf.Tensor, tf.Variable, tf.Operation))
def shape_to_list(shape: Iterable[tf.Dimension]) -> List[Union[int, None]]:
"""Convert a Tensorflow shape to a list of ints. Retained for backwards compatibility -- use TensorShape.as_list() in new code."""
return [dim.value for dim in shape]
def flatten(x: TfExpressionEx) -> TfExpression:
"""Shortcut function for flattening a tensor."""
with tf.name_scope("Flatten"):
return tf.reshape(x, [-1])
def log2(x: TfExpressionEx) -> TfExpression:
"""Logarithm in base 2."""
with tf.name_scope("Log2"):
return tf.log(x) * np.float32(1.0 / np.log(2.0))
def exp2(x: TfExpressionEx) -> TfExpression:
"""Exponent in base 2."""
with tf.name_scope("Exp2"):
return tf.exp(x * np.float32(np.log(2.0)))
def erfinv(y: TfExpressionEx) -> TfExpression:
"""Inverse of the error function."""
# pylint: disable=no-name-in-module
from tensorflow.python.ops.distributions import special_math
return special_math.erfinv(y)
def lerp(a: TfExpressionEx, b: TfExpressionEx, t: TfExpressionEx) -> TfExpressionEx:
"""Linear interpolation."""
with tf.name_scope("Lerp"):
return a + (b - a) * t
def lerp_clip(a: TfExpressionEx, b: TfExpressionEx, t: TfExpressionEx) -> TfExpression:
"""Linear interpolation with clip."""
with tf.name_scope("LerpClip"):
return a + (b - a) * tf.clip_by_value(t, 0.0, 1.0)
def absolute_name_scope(scope: str) -> tf.name_scope:
"""Forcefully enter the specified name scope, ignoring any surrounding scopes."""
return tf.name_scope(scope + "/")
def absolute_variable_scope(scope: str, **kwargs) -> tf.variable_scope:
"""Forcefully enter the specified variable scope, ignoring any surrounding scopes."""
return tf.variable_scope(tf.VariableScope(name=scope, **kwargs), auxiliary_name_scope=False)
def _sanitize_tf_config(config_dict: dict = None) -> dict:
# Defaults.
cfg = dict()
cfg["rnd.np_random_seed"] = None # Random seed for NumPy. None = keep as is.
cfg["rnd.tf_random_seed"] = "auto" # Random seed for TensorFlow. 'auto' = derive from NumPy random state. None = keep as is.
cfg["env.TF_CPP_MIN_LOG_LEVEL"] = "1" # 0 = Print all available debug info from TensorFlow. 1 = Print warnings and errors, but disable debug info.
cfg["env.HDF5_USE_FILE_LOCKING"] = "FALSE" # Disable HDF5 file locking to avoid concurrency issues with network shares.
cfg["graph_options.place_pruned_graph"] = True # False = Check that all ops are available on the designated device. True = Skip the check for ops that are not used.
cfg["gpu_options.allow_growth"] = True # False = Allocate all GPU memory at the beginning. True = Allocate only as much GPU memory as needed.
# Remove defaults for environment variables that are already set.
for key in list(cfg):
fields = key.split(".")
if fields[0] == "env":
assert len(fields) == 2
if fields[1] in os.environ:
del cfg[key]
# User overrides.
if config_dict is not None:
cfg.update(config_dict)
return cfg
def init_tf(config_dict: dict = None) -> None:
"""Initialize TensorFlow session using good default settings."""
# Skip if already initialized.
if tf.get_default_session() is not None:
return
# Setup config dict and random seeds.
cfg = _sanitize_tf_config(config_dict)
np_random_seed = cfg["rnd.np_random_seed"]
if np_random_seed is not None:
np.random.seed(np_random_seed)
tf_random_seed = cfg["rnd.tf_random_seed"]
if tf_random_seed == "auto":
tf_random_seed = np.random.randint(1 << 31)
if tf_random_seed is not None:
tf.set_random_seed(tf_random_seed)
# Setup environment variables.
for key, value in cfg.items():
fields = key.split(".")
if fields[0] == "env":
assert len(fields) == 2
os.environ[fields[1]] = str(value)
# Create default TensorFlow session.
create_session(cfg, force_as_default=True)
def assert_tf_initialized():
"""Check that TensorFlow session has been initialized."""
if tf.get_default_session() is None:
raise RuntimeError("No default TensorFlow session found. Please call dnnlib.tflib.init_tf().")
def create_session(config_dict: dict = None, force_as_default: bool = False) -> tf.Session:
"""Create tf.Session based on config dict."""
# Setup TensorFlow config proto.
cfg = _sanitize_tf_config(config_dict)
config_proto = tf.ConfigProto()
for key, value in cfg.items():
fields = key.split(".")
if fields[0] not in ["rnd", "env"]:
obj = config_proto
for field in fields[:-1]:
obj = getattr(obj, field)
setattr(obj, fields[-1], value)
# Create session.
session = tf.Session(config=config_proto)
if force_as_default:
# pylint: disable=protected-access
session._default_session = session.as_default()
session._default_session.enforce_nesting = False
session._default_session.__enter__()
return session
def init_uninitialized_vars(target_vars: List[tf.Variable] = None) -> None:
"""Initialize all tf.Variables that have not already been initialized.
Equivalent to the following, but more efficient and does not bloat the tf graph:
tf.variables_initializer(tf.report_uninitialized_variables()).run()
"""
assert_tf_initialized()
if target_vars is None:
target_vars = tf.global_variables()
test_vars = []
test_ops = []
with tf.control_dependencies(None): # ignore surrounding control_dependencies
for var in target_vars:
assert is_tf_expression(var)
try:
tf.get_default_graph().get_tensor_by_name(var.name.replace(":0", "/IsVariableInitialized:0"))
except KeyError:
# Op does not exist => variable may be uninitialized.
test_vars.append(var)
with absolute_name_scope(var.name.split(":")[0]):
test_ops.append(tf.is_variable_initialized(var))
init_vars = [var for var, inited in zip(test_vars, run(test_ops)) if not inited]
run([var.initializer for var in init_vars])
def set_vars(var_to_value_dict: dict) -> None:
"""Set the values of given tf.Variables.
Equivalent to the following, but more efficient and does not bloat the tf graph:
tflib.run([tf.assign(var, value) for var, value in var_to_value_dict.items()]
"""
assert_tf_initialized()
ops = []
feed_dict = {}
for var, value in var_to_value_dict.items():
assert is_tf_expression(var)
try:
setter = tf.get_default_graph().get_tensor_by_name(var.name.replace(":0", "/setter:0")) # look for existing op
except KeyError:
with absolute_name_scope(var.name.split(":")[0]):
with tf.control_dependencies(None): # ignore surrounding control_dependencies
setter = tf.assign(var, tf.placeholder(var.dtype, var.shape, "new_value"), name="setter") # create new setter
ops.append(setter)
feed_dict[setter.op.inputs[1]] = value
run(ops, feed_dict)
def create_var_with_large_initial_value(initial_value: np.ndarray, *args, **kwargs):
"""Create tf.Variable with large initial value without bloating the tf graph."""
assert_tf_initialized()
assert isinstance(initial_value, np.ndarray)
zeros = tf.zeros(initial_value.shape, initial_value.dtype)
var = tf.Variable(zeros, *args, **kwargs)
set_vars({var: initial_value})
return var
def convert_images_from_uint8(images, drange=[-1,1], nhwc_to_nchw=False):
"""Convert a minibatch of images from uint8 to float32 with configurable dynamic range.
Can be used as an input transformation for Network.run().
"""
images = tf.cast(images, tf.float32)
if nhwc_to_nchw:
images = tf.transpose(images, [0, 3, 1, 2])
return images * ((drange[1] - drange[0]) / 255) + drange[0]
def convert_images_to_uint8(images, drange=[-1,1], nchw_to_nhwc=False, shrink=1):
"""Convert a minibatch of images from float32 to uint8 with configurable dynamic range.
Can be used as an output transformation for Network.run().
"""
images = tf.cast(images, tf.float32)
if shrink > 1:
ksize = [1, 1, shrink, shrink]
images = tf.nn.avg_pool(images, ksize=ksize, strides=ksize, padding="VALID", data_format="NCHW")
if nchw_to_nhwc:
images = tf.transpose(images, [0, 2, 3, 1])
scale = 255 / (drange[1] - drange[0])
images = images * scale + (0.5 - drange[0] * scale)
return tf.saturate_cast(images, tf.uint8)