To improve efficiency for solving a system of equations, art equation solver uses variable reduction techniques to reduce a number of variables to be solved. The equation solver identifies derived variables and eliminates them from the system of equations. The equation solver considers the remaining variables to be primitive variables. The primitive variables may be rewritten into a representation of the system of equations or into a set of equations that may be used to solve for values of the primitive variables. The equation solver solves for values of the primitive variables. Prior to solving or during solving iterations, the equation solver may apply storage policies to further reduce the number of variables to be solved. The storage policies indicate parameters and techniques for eliminating primitive variables to be solved, such as primitive variables that are insignificant (i.e., have little effect on a solution for the system of equations).