With this method, the spatial variation of the state and flux variables are defined in terms of the nodal values of the quantities and a local interpolation function.[^1] If the input is and the state vector is then the discretization is
Where is the interpolation function that has a value of 1 at the node and 0 elsewhere.[^1] The equations are projected onto a test function and integrated over a domain.[^1]
Where is the mass matrix, and the matrices are the residual matrices defined by integration over the entire domain.[^1]