Abstract: Due to the instability of the residuals aroused in the conjugate gradient square method, we present a new method named MR-CGS, which has the minimal residual property while retaining the square converging property. Finally, an example is given to exhibit the application of the improved algorithm in solving the DDM model.

Key words: semiconductor device, sparse matrix, BiCG, iterative algorithm, MR-CGS, numerical simulation, CGS