ray/rllib/models/tf/misc.py

88 lines
2.6 KiB
Python

import numpy as np
from typing import Tuple, Any, Optional
from ray.rllib.utils.annotations import DeveloperAPI
from ray.rllib.utils.framework import try_import_tf
from ray.rllib.utils.typing import TensorType
tf1, tf, tfv = try_import_tf()
@DeveloperAPI
def normc_initializer(std: float = 1.0) -> Any:
def _initializer(shape, dtype=None, partition_info=None):
out = np.random.randn(*shape).astype(
dtype.name if hasattr(dtype, "name") else dtype or np.float32
)
out *= std / np.sqrt(np.square(out).sum(axis=0, keepdims=True))
return tf.constant(out)
return _initializer
@DeveloperAPI
def conv2d(
x: TensorType,
num_filters: int,
name: str,
filter_size: Tuple[int, int] = (3, 3),
stride: Tuple[int, int] = (1, 1),
pad: str = "SAME",
dtype: Optional[Any] = None,
collections: Optional[Any] = None,
) -> TensorType:
if dtype is None:
dtype = tf.float32
with tf1.variable_scope(name):
stride_shape = [1, stride[0], stride[1], 1]
filter_shape = [
filter_size[0],
filter_size[1],
int(x.get_shape()[3]),
num_filters,
]
# There are "num input feature maps * filter height * filter width"
# inputs to each hidden unit.
fan_in = np.prod(filter_shape[:3])
# Each unit in the lower layer receives a gradient from: "num output
# feature maps * filter height * filter width" / pooling size.
fan_out = np.prod(filter_shape[:2]) * num_filters
# Initialize weights with random weights.
w_bound = np.sqrt(6 / (fan_in + fan_out))
w = tf1.get_variable(
"W",
filter_shape,
dtype,
tf1.random_uniform_initializer(-w_bound, w_bound),
collections=collections,
)
b = tf1.get_variable(
"b",
[1, 1, 1, num_filters],
initializer=tf1.constant_initializer(0.0),
collections=collections,
)
return tf1.nn.conv2d(x, w, stride_shape, pad) + b
@DeveloperAPI
def linear(
x: TensorType,
size: int,
name: str,
initializer: Optional[Any] = None,
bias_init: float = 0.0,
) -> TensorType:
w = tf1.get_variable(name + "/w", [x.get_shape()[1], size], initializer=initializer)
b = tf1.get_variable(
name + "/b", [size], initializer=tf1.constant_initializer(bias_init)
)
return tf.matmul(x, w) + b
@DeveloperAPI
def flatten(x: TensorType) -> TensorType:
return tf.reshape(x, [-1, np.prod(x.get_shape().as_list()[1:])])