Compute a preconditioner using a modified incomplete Cholesky decomposition. [M1,M2] = divand_pc_michol(iB,H,R,icholparam) Compute preconditioner matrices M1 and M2 based on the inverse background error covariance iB, observation operator H and observation R covariance R. icholparam is a structure will parameters for ichol. The default value is struct('michol','on'). A modified incomplete Cholesky factorization of the matrix iP = iB + H'*(R\H) is computed per default. M2 is the transpose of M1 for this preconditioner. The function ichol is necessary. See also: ichol, divand_pc_sqrtiB
Package: divand