Smooth l1 loss
\[
\ell(x, y) = L = \{l_1, ..., l_N\}^T
\]
With
\[
l_n = \begin{cases}
0.5 (x_n - y_n)^2 / beta, & \text{if } |x_n - y_n| < beta \\
|x_n - y_n| - 0.5 * beta, & \text{otherwise }
\end{cases}
\]
If reduction is not none, then:
\[
\ell(x, y) =
\begin{cases}
\operatorname{mean}(L), & \text{if reduction} = \text{`mean';}\\
\operatorname{sum}(L), & \text{if reduction} = \text{`sum'.}
\end{cases}
\]
等有机会 plot 一下。
最后更新:
2023-01-31