On the CRI method for solving Sylvester equation with complex symmetric positive semi-definite coefficient matrices

Combination of real and imaginary parts (CRI) method is an efficient for solving a class large sparse linear systems with complex symmetric positive semi-definite coefficient matrices. In this work we will extend CRI approach to determine the approximate solution Sylvester equation We show that new algorithm converges unconditionally unique exact matrix equation. end test scheme by some numerical examples.