**DouZero** is an AI system for the card game DouDizhu that enhances traditional Monte-Carlo methods with deep neural networks, action encoding, and parallel actors. The [Q-network](https://paperswithcode.com/method/dqn) of DouZero consists of an [LSTM](https://paperswithcode.com/method/lstm) to encode historical actions and six layers of [MLP](https://paperswithcode.com/method/feedforward-network) with hidden dimension of 512. The network predicts a value for a given state-action pair based on the concatenated representation of action and state.

**FBNet** is a type of convolutional neural architectures discovered through [DNAS](https://paperswithcode.com/method/dnas) [neural architecture search](https://paperswithcode.com/method/neural-architecture-search). It utilises a basic type of image model block inspired by [MobileNetv2](https://paperswithcode.com/method/mobilenetv2) that utilises depthwise convolutions and an inverted residual structure (see components).

FBNet

FBNet: Hardware-Aware Efficient ConvNet Design via Differentiable Neural Architecture Search

DouZero

DouZero: Mastering DouDizhu with Self-Play Deep Reinforcement Learning

The **Gaussian Error Linear Unit**, or **GELU**,  is an activation function. The GELU activation function is $x\Phi(x)$, where $\Phi(x)$ the standard Gaussian cumulative distribution function. The GELU nonlinearity weights inputs by their percentile, rather than gates inputs by their sign as in [ReLUs](https://paperswithcode.com/method/relu) ($x\mathbf{1}_{x>0}$). Consequently the GELU can be thought of as a smoother ReLU.

$$\text{GELU}\left(x\right) = x{P}\left(X\leq{x}\right) = x\Phi\left(x\right) = x \cdot \frac{1}{2}\left[1 + \text{erf}(x/\sqrt{2})\right],$$
if $X\sim \mathcal{N}(0,1)$.

One can approximate the GELU with
$0.5x\left(1+\tanh\left[\sqrt{2/\pi}\left(x + 0.044715x^{3}\right)\right]\right)$ or $x\sigma\left(1.702x\right),$
but PyTorch's exact implementation is sufficiently fast such that these approximations may be unnecessary. (See also the [SiLU](https://paperswithcode.com/method/silu) $x\sigma(x)$ which was also coined in the paper that introduced the GELU.)

GELUs are used in [GPT-3](https://paperswithcode.com/method/gpt-3), [BERT](https://paperswithcode.com/method/bert), and most other Transformers.

Source	DouZero: Mastering DouDizhu with Self-Play Deep Reinforcement Learning
Year	2000
Data Source	CC BY-SA - https://paperswithcode.com