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BSpar_isolve(3) BlockSolve95 BSpar_isolve(3)## NAME

BSpar_isolve - Solve a symmetric indefinite system of equations using symmlq preconditioned by one of several preconditioners.## INPUT PARAMETERS

A- a sparse matrixfact_A- the incomplete factored version of A, if any (NULL if not exist)comm_A- the communication structure for AB- a sparse matrixcomm_B- the communication structure for Bin_rhs- the rhsshift- the shift to multiply B bypre_option- the preconditioner to use PRE_ICC: incomplete Cholesky factorization of A PRE_ILU: incomplete LU factorization of A PRE_SSOR: Successive over relaxation (using just A) PRE_BJACOBI: Block Jacobi (using just A)residual- the final computed residualprocinfo- the usual processor stuff## OUTPUT PARAMETERS

out_x- the solution vector## RETURNS

The number of iterations.## NOTES

The system solved is (A-shift*B)out_x = in_rhs. The preconditioners must be computed prior to calling BSpar_isolve. For more information on the preconditioners, see the manual. The following are now specified in the context: err_tol - the tolerance to which to solve the problem stop if the estimated norm of the residual divided by the norm of the rhs is less than err_tol max_iter - the maximum number of iterations to take guess - if TRUE, then initialize out_x to 0, otherwise the program assumes that out_x contains an initial guess## SYNOPSIS

int BSpar_isolve(BSpar_mat *A, BSpar_mat *fact_A, BScomm *comm_A, BSpar_mat *B, BScomm *comm_B, FLOAT *in_rhs, FLOAT *out_x, FLOAT shift, FLOAT *residual, BSprocinfo *procinfo)## LOCATION

BlockSolve95/src/BSpar_isolve.c 4/4/1996 BSpar_isolve(3)

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