# How to efficently solve: min $\sum_{ij}(a_{ij}x_{ij}^2 + b_{ij}x_{ij})$ s.t

I am trying to solve the following problem, where $a_{ij} \ge 0 \ \forall i,j$: \begin{align} \mbox{minimize}\quad & \sum_{i=1}^m\sum_{j=1}^n (a_{ij}x_{ij}^2 + b_{ij}x_{ij})\\ \mbox{subject to}\quad &\sum_{i=1}^m x_{ij} \le 1 \quad \forall j,\\ &\sum_{j=1}^n x_{ij} \le 1\quad \forall i,\\ &x_{ij} \ge 0 \quad \forall i,j.\end{align} Could you please suggest me with some methods? (The faster the better.)