{%hackmd @themes/dracula %}

## NLLLoss

$l_n = -w_{y_n}x_{n, y_n}$

## CrossEntropyLoss = logSoftmax + NLLLoss

loss = $\sum p(x)logq(x)$

## KL

loss = $\sum p_klog\frac{p_k}{q_k}$ = $\sum p_k(logp_k-logq_k)$