This essentially reformulates the problem into a system of linear equations, which can be solved using numerous methods such as Gaussian elimination; in practice advanced methods like the block Lanczos algorithm are used, that take advantage of certain properties of the system.
This essentially rephrases the problem into a set of linear equations, which can be solved through various methods such as Gaussian elimination; in practice, sophisticated techniques like the block Lanczos algorithm are employed, leveraging specific properties of the system.