# 向量, 矩阵与张量梯度的理论推导

## 基本思路

In order to simplify a given calculation, it is often useful to write out the explicit formula for a single scalar element of the output in terms of nothing but scalar variables. Once one has an explicit formula for a single scalar element of the output in terms of other scalar values, then one can use the calculus that you used as a beginner, which is much easier than trying to do matrix math, summations, and derivatives all at the same time.

## 例子

${\bf X}: B \times N$矩阵, ${\bf W}: N \times M$矩阵, ${\bf Y}: B\times M$矩阵, 而$\tilde{ {\bf Y} }$表示如下:

### 结合

Ph.D candidate of EIC at HUST.