每行为一个多元函数（多元函数为向量值函数$f:\mathbb R^n\to \mathbb R^m$的$m$个分量之一）的梯度转置$Df_i(\boldsymbol x_0)$

$$ \mathbf{J}=\begin{bmatrix}\dfrac{\partial f}{\partial x_1}(\boldsymbol{x}_0)&\cdots&\dfrac{\partial f}{\partial x_n}(\boldsymbol{x}_0)\\\vdots&&\vdots\\\frac{\partial f_m}{\partial x_1}(\boldsymbol{x}_0)&\cdots&\frac{\partial f_m}{\partial x_n}(\boldsymbol{x}_0)\end{bmatrix}=\begin{bmatrix} \nabla f(\boldsymbol{x}_0)^T\\ \nabla f_2(\boldsymbol{x}_0)^T \\ \cdots \\ \nabla f_m(\boldsymbol{x}_0)^T \end{bmatrix}=\begin{bmatrix}\frac{\partial\mathbf{f}}{\partial x_1}&\cdots&\frac{\partial\mathbf{f}}{\partial x_n}\end{bmatrix} $$