mean = (

pt.wrap(obs).fully_connected(64, activation_fn=tf.nn.relu, stddev=0.01).

fully_connected(64, activation_fn=tf.nn.relu, stddev=0.01).

fully_connected(action_dim, activation_fn=None, stddev=0.01))

action_dist_logstd_param = tf.Variable((.01*np.random.randn(1, action_dim)).astype(np.float32))

action_dist_logstd = tf.tile(action_dist_logstd_param, tf.pack((tf.shape(mean)[0], 1)))

std = tf.exp(action_dist_logstd)