$$\text{均方误差}＝\underset{我＝1}{\overset{R}{{\displaystyle \sum }}}\frac{{（t_{我}-y_{我}）}^2}{R}，$$

$$\text{损失}＝\frac{1}{2}\underset{我＝1}{\overset{R}{{\displaystyle \sum }}}{（t_{我}-y_{我}）}^2．$$

$$\text{损失}＝\frac{1}{2}\underset{p＝1}{\overset{HWC}{{\displaystyle \sum }}}{（t_p-y_p）}^2，$$

$$\text{损失}＝\frac{1}{2\mathrm{年代}}\underset{我＝1}{\overset{\mathrm{年代}}{{\displaystyle \sum }}}\underset{j＝1}{\overset{R}{{\displaystyle \sum }}}{（t_{我j}-y_{我j}）}^2，$$