"shared": false, // whether to shared networks for Actor-Critic
"fc_hid_layers": [512, 256],
"hid_layers_activation": "relu",
"out_layer_activation": null,
"init_fn": null, // weight initialization
"normalize": false, // whether to divide input by 255.0
"batch_norm": false, // whether to add batchnorm layers
"clip_grad_val": 1.0, // clip gradient by norm
"name": "SmoothL1Loss" // default loss function used for regression
"optim_spec": { // the optimizer and its arguments