Given an $NxN$ matrix $A$ and vectors $u,v,b$ such that: $$u_i = {\frac1{a_{ii}}}(b_i - \sum_{j=1,j\neq{i}}^n a_{ij}v_i)$$
And considering $A$ is stored using CRS, provide an algorithm (or pseudocode) for calculating $u$.
I am struggling with understanding the above problem and the relation between CRS (Compressed Row Storage) and the presented formula. Looking around for resources, I found a somewhat similar formula used in the Gauss–Seidel method, however I am not familiar with it and I'm not sure if it has anything to do with the above problem. I am assuming that the algorithm should be iterative.
Thanks in advance for any help.