Preconditioned GSOR iterative method for a class of complex symmetric   system of linear equations
  In this paper, we present a preconditioned variant of the generalized successive overrelaxation (GSOR) iterative method for solving a broad class of complex symmetric linear systems. We study conditions under which the spectral radius of the iteration matrix of the preconditioned GSOR method is smaller than that of the GSOR method and determine the optimal values of iteration parameters. Numerical experiments are given to verify the validity of the presented theoretical results and the effectiveness of the preconditioned GSOR method. 
Davod Hezari, Vahid Edalatpour and Davod Khojasteh Salkuyeh
math.NA