"""GaussianMLPRegressorModel."""
import numpy as np
import tensorflow as tf
import tensorflow_probability as tfp
from garage.tf.models import GaussianMLPModel
[docs]class GaussianMLPRegressorModel(GaussianMLPModel):
"""GaussianMLPRegressor based on garage.tf.models.Model class.
This class can be used to perform regression by fitting a Gaussian
distribution to the outputs.
Args:
input_shape (tuple[int]): Input shape of the training data.
output_dim (int): Output dimension of the model.
name (str): Model name, also the variable scope.
hidden_sizes (list[int]): Output dimension of dense layer(s) for
the MLP for mean. For example, (32, 32) means the MLP consists
of two hidden layers, each with 32 hidden units.
hidden_nonlinearity (callable): Activation function for intermediate
dense layer(s). It should return a tf.Tensor. Set it to
None to maintain a linear activation.
hidden_w_init (callable): Initializer function for the weight
of intermediate dense layer(s). The function should return a
tf.Tensor.
hidden_b_init (callable): Initializer function for the bias
of intermediate dense layer(s). The function should return a
tf.Tensor.
output_nonlinearity (callable): Activation function for output dense
layer. It should return a tf.Tensor. Set it to None to
maintain a linear activation.
output_w_init (callable): Initializer function for the weight
of output dense layer(s). The function should return a
tf.Tensor.
output_b_init (callable): Initializer function for the bias
of output dense layer(s). The function should return a
tf.Tensor.
learn_std (bool): Is std trainable.
init_std (float): Initial value for std.
adaptive_std (bool): Is std a neural network. If False, it will be a
parameter.
std_share_network (bool): Boolean for whether mean and std share
the same network.
std_hidden_sizes (list[int]): Output dimension of dense layer(s) for
the MLP for std. For example, (32, 32) means the MLP consists
of two hidden layers, each with 32 hidden units.
min_std (float): If not None, the std is at least the value of min_std,
to avoid numerical issues.
max_std (float): If not None, the std is at most the value of max_std,
to avoid numerical issues.
std_hidden_nonlinearity (callable): Nonlinearity for each hidden layer
in the std network.
std_hidden_w_init (callable): Initializer function for the weight
of intermediate dense layer(s) in the std network.
std_hidden_b_init (callable): Initializer function for the bias
of intermediate dense layer(s) in the std network.
std_output_nonlinearity (callable): Activation function for output
dense layer in the std network. It should return a tf.Tensor. Set
it to None to maintain a linear activation.
std_output_w_init (callable): Initializer function for the weight
of output dense layer(s) in the std network.
std_parameterization (str): How the std should be parametrized. There
are two options:
- exp: the logarithm of the std will be stored, and applied a
exponential transformation
- softplus: the std will be computed as log(1+exp(x))
layer_normalization (bool): Bool for using layer normalization or not.
"""
def __init__(self,
input_shape,
output_dim,
name='GaussianMLPRegressorModel',
hidden_sizes=(32, 32),
hidden_nonlinearity=tf.nn.tanh,
hidden_w_init=tf.initializers.glorot_uniform(),
hidden_b_init=tf.zeros_initializer(),
output_nonlinearity=None,
output_w_init=tf.initializers.glorot_uniform(),
output_b_init=tf.zeros_initializer(),
learn_std=True,
adaptive_std=False,
std_share_network=False,
init_std=1.0,
min_std=1e-6,
max_std=None,
std_hidden_sizes=(32, 32),
std_hidden_nonlinearity=tf.nn.tanh,
std_hidden_w_init=tf.initializers.glorot_uniform(),
std_hidden_b_init=tf.zeros_initializer(),
std_output_nonlinearity=None,
std_output_w_init=tf.initializers.glorot_uniform(),
std_parameterization='exp',
layer_normalization=False):
super().__init__(output_dim=output_dim,
name=name,
hidden_sizes=hidden_sizes,
hidden_nonlinearity=hidden_nonlinearity,
hidden_w_init=hidden_w_init,
hidden_b_init=hidden_b_init,
output_nonlinearity=output_nonlinearity,
output_w_init=output_w_init,
output_b_init=output_b_init,
learn_std=learn_std,
adaptive_std=adaptive_std,
std_share_network=std_share_network,
init_std=init_std,
min_std=min_std,
max_std=max_std,
std_hidden_sizes=std_hidden_sizes,
std_hidden_nonlinearity=std_hidden_nonlinearity,
std_output_nonlinearity=std_output_nonlinearity,
std_parameterization=std_parameterization,
layer_normalization=layer_normalization)
self._input_shape = input_shape
[docs] def network_output_spec(self):
"""Network output spec.
Return:
list[str]: List of key(str) for the network outputs.
"""
return [
'normalized_dist', 'normalized_mean', 'normalized_log_std', 'dist',
'mean', 'log_std', 'x_mean', 'x_std', 'y_mean', 'y_std'
]
def _build(self, state_input, name=None):
"""Build model given input placeholder(s).
Args:
state_input (tf.Tensor): Place holder for state input.
name (str): Inner model name, also the variable scope of the
inner model, if exist. One example is
garage.tf.models.Sequential.
Return:
tfp.distributions.MultivariateNormalDiag: Normlizaed distribution.
tf.Tensor: Normalized mean.
tf.Tensor: Normalized log_std.
tfp.distributions.MultivariateNormalDiag: Vanilla distribution.
tf.Tensor: Vanilla mean.
tf.Tensor: Vanilla log_std.
tf.Tensor: Mean for data.
tf.Tensor: log_std for data.
tf.Tensor: Mean for label.
tf.Tensor: log_std for label.
"""
with tf.compat.v1.variable_scope('normalized_vars'):
x_mean_var = tf.compat.v1.get_variable(
name='x_mean',
shape=(1, ) + self._input_shape,
dtype=np.float32,
initializer=tf.zeros_initializer(),
trainable=False)
x_std_var = tf.compat.v1.get_variable(
name='x_std_var',
shape=(1, ) + self._input_shape,
dtype=np.float32,
initializer=tf.ones_initializer(),
trainable=False)
y_mean_var = tf.compat.v1.get_variable(
name='y_mean_var',
shape=(1, self._output_dim),
dtype=np.float32,
initializer=tf.zeros_initializer(),
trainable=False)
y_std_var = tf.compat.v1.get_variable(
name='y_std_var',
shape=(1, self._output_dim),
dtype=np.float32,
initializer=tf.ones_initializer(),
trainable=False)
normalized_xs_var = (state_input - x_mean_var) / x_std_var
_, normalized_dist_mean, normalized_dist_log_std = super()._build(
normalized_xs_var)
# Since regressor expects [N, *dims], we need to squeeze the extra
# dimension
normalized_dist_log_std = tf.squeeze(normalized_dist_log_std, 1)
with tf.name_scope('mean_network'):
means_var = normalized_dist_mean * y_std_var + y_mean_var
with tf.name_scope('std_network'):
log_stds_var = normalized_dist_log_std + tf.math.log(y_std_var)
normalized_dist = tfp.distributions.MultivariateNormalDiag(
loc=normalized_dist_mean,
scale_diag=tf.exp(normalized_dist_log_std))
vanilla_dist = tfp.distributions.MultivariateNormalDiag(
loc=means_var, scale_diag=tf.exp(log_stds_var))
return (normalized_dist, normalized_dist_mean, normalized_dist_log_std,
vanilla_dist, means_var, log_stds_var, x_mean_var, x_std_var,
y_mean_var, y_std_var)
[docs] def clone(self, name):
"""Return a clone of the model.
It only copies the configuration of the primitive,
not the parameters.
Args:
name (str): Name of the newly created model. It has to be
different from source model if cloned under the same
computational graph.
Returns:
garage.tf.policies.GaussianMLPModel: Newly cloned model.
"""
return self.__class__(
name=name,
input_shape=self._input_shape,
output_dim=self._output_dim,
hidden_sizes=self._hidden_sizes,
hidden_nonlinearity=self._hidden_nonlinearity,
hidden_w_init=self._hidden_w_init,
hidden_b_init=self._hidden_b_init,
output_nonlinearity=self._output_nonlinearity,
output_w_init=self._output_w_init,
output_b_init=self._output_b_init,
learn_std=self._learn_std,
adaptive_std=self._adaptive_std,
std_share_network=self._std_share_network,
init_std=self._init_std,
min_std=self._min_std,
max_std=self._max_std,
std_hidden_sizes=self._std_hidden_sizes,
std_hidden_nonlinearity=self._std_hidden_nonlinearity,
std_hidden_w_init=self._std_hidden_w_init,
std_hidden_b_init=self._std_hidden_b_init,
std_output_nonlinearity=self._std_output_nonlinearity,
std_output_w_init=self._std_output_w_init,
std_parameterization=self._std_parameterization,
layer_normalization=self._layer_normalization)