!!$ !!$ !!$ MLD2P4 !!$ MultiLevel Domain Decomposition Parallel Preconditioners Package !!$ based on PSBLAS (Parallel Sparse BLAS v.2.0) !!$ !!$ (C) Copyright 2007 Alfredo Buttari University of Rome Tor Vergata !!$ Pasqua D'Ambra ICAR-CNR, Naples !!$ Daniela di Serafino Second University of Naples !!$ Salvatore Filippone University of Rome Tor Vergata !!$ !!$ Redistribution and use in source and binary forms, with or without !!$ modification, are permitted provided that the following conditions !!$ are met: !!$ 1. Redistributions of source code must retain the above copyright !!$ notice, this list of conditions and the following disclaimer. !!$ 2. Redistributions in binary form must reproduce the above copyright !!$ notice, this list of conditions, and the following disclaimer in the !!$ documentation and/or other materials provided with the distribution. !!$ 3. 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File: mld_dilu_bld.f90 ! ! Subroutine: mld_dilu_bld ! Version: real ! ! This routine computes an incomplete LU (ILU) factorization of the local part ! of the matrix stored into a. This factorization is used to build the 'base ! preconditioner' (block-Jacobi preconditioner/solver, Additive Schwarz ! preconditioner) corresponding to a certain level of a multilevel preconditioner. ! The following factorizations are available: ! - ILU(k), i.e. ILU factorization with fill-in level k, ! - MILU(k), i.e. modified ILU factorization with fill-in level k, ! - ILU(k,t), i.e. ILU with threshold (i.e. drop tolerance) t and k additional ! entries in each row of the L and U factors with respect to the initial ! sparsity pattern. ! Note that the meaning of k in ILU(k,t) is different from that in ILU(k) and ! MILU(k). ! ! For details on the above factorizations see ! Y. Saad, Iterative Methods for Sparse Linear Systems, Second Edition, ! SIAM, 2003, Chapter 10. ! ! Note that that this routine handles the ILU(0) factorization separately, ! through mld_ilu0_fact, for performance reasons. ! ! ! Arguments: ! a - type(psb_dspmat_type), input. ! The sparse matrix structure containing the local matrix to be ! factorized. Note that if p%iprcparm(mld_n_ovr_) > 0, i.e. the ! 'base' Additive Schwarz preconditioner has overlap greater than ! 0, and p%iprcparm(mld_sub_ren_) = 0, i.e. a reordering of the ! matrix has not been performed (see mld_bjac_bld), then a contains ! only the 'original' local part of the matrix to be factorized, ! i.e. the rows of the matrix held by the calling process according ! to the initial data distribution. ! p - type(mld_dbaseprc_type), input/output. ! The 'base preconditioner' data structure. In input, p%iprcparm ! contains information on the type of factorization to be computed. ! In output, p%av(mld_l_pr_) and p%av(mld_u_pr_) contain the ! incomplete L and U factors (without their diagonals), and p%d ! contains the diagonal of the incomplete U factor. For more ! details on p see its description in mld_prec_type.f90. ! info - integer, output. ! Error code. ! blck - type(psb_dspmat_type), input, optional. ! The sparse matrix structure containing the remote rows of the ! matrix to be factorized, that have been retrieved by mld_asmat_bld ! to build an Additive Schwarz base preconditioner with overlap ! greater than 0. If the overlap is 0 or the matrix has been reordered ! (see mld_bjac_bld), then blck does not contain any row. ! subroutine mld_dilu_bld(a,p,upd,info,blck) use psb_base_mod use mld_prec_mod, mld_protect_name => mld_dilu_bld implicit none ! Arguments type(psb_dspmat_type), intent(in), target :: a type(mld_dbaseprc_type), intent(inout) :: p character, intent(in) :: upd integer, intent(out) :: info type(psb_dspmat_type), intent(in), optional :: blck ! Local Variables integer :: i, nztota, err_act, n_row, nrow_a character :: trans, unitd integer :: debug_level, debug_unit integer :: ictxt,np,me character(len=20) :: name, ch_err if(psb_get_errstatus().ne.0) return info=0 name='mld_dilu_bld' call psb_erractionsave(err_act) debug_unit = psb_get_debug_unit() debug_level = psb_get_debug_level() ictxt = psb_cd_get_context(p%desc_data) call psb_info(ictxt, me, np) if (debug_level >= psb_debug_outer_) & & write(debug_unit,*) me,' ',trim(name),' start' trans = 'N' unitd = 'U' ! ! Check the memory available to hold the incomplete L and U factors ! and allocate it if needed ! if (allocated(p%av)) then if (size(p%av) < mld_bp_ilu_avsz_) then do i=1,size(p%av) call psb_sp_free(p%av(i),info) if (info /= 0) then ! Actually, we don't care here about this. Just let it go. ! return end if enddo deallocate(p%av,stat=info) endif end if if (.not.allocated(p%av)) then allocate(p%av(mld_max_avsz_),stat=info) if (info /= 0) then call psb_errpush(4000,name) goto 9999 end if endif nrow_a = psb_sp_get_nrows(a) nztota = psb_sp_get_nnzeros(a) if (present(blck)) then nztota = nztota + psb_sp_get_nnzeros(blck) end if if (debug_level >= psb_debug_outer_) & & write(debug_unit,*) me,' ',trim(name),& & ': out get_nnzeros',nztota,a%m,a%k,nrow_a n_row = p%desc_data%matrix_data(psb_n_row_) p%av(mld_l_pr_)%m = n_row p%av(mld_l_pr_)%k = n_row p%av(mld_u_pr_)%m = n_row p%av(mld_u_pr_)%k = n_row call psb_sp_all(n_row,n_row,p%av(mld_l_pr_),nztota,info) if (info == 0) call psb_sp_all(n_row,n_row,p%av(mld_u_pr_),nztota,info) if(info/=0) then info=4010 ch_err='psb_sp_all' call psb_errpush(info,name,a_err=ch_err) goto 9999 end if if (allocated(p%d)) then if (size(p%d) < n_row) then deallocate(p%d) endif endif if (.not.allocated(p%d)) then allocate(p%d(n_row),stat=info) if (info /= 0) then call psb_errpush(4010,name,a_err='Allocate') goto 9999 end if endif select case(p%iprcparm(mld_sub_solve_)) case (mld_ilu_t_) ! ! ILU(k,t) ! select case(p%iprcparm(mld_sub_fill_in_)) case(:-1) ! Error: fill-in <= -1 call psb_errpush(30,name,i_err=(/3,p%iprcparm(mld_sub_fill_in_),0,0,0/)) goto 9999 case(0:) ! Fill-in >= 0 call mld_ilut_fact(p%iprcparm(mld_sub_fill_in_),p%dprcparm(mld_fact_thrs_),& & a, p%av(mld_l_pr_),p%av(mld_u_pr_),p%d,info,blck=blck) end select if(info/=0) then info=4010 ch_err='mld_ilut_fact' call psb_errpush(info,name,a_err=ch_err) goto 9999 end if case(mld_ilu_n_,mld_milu_n_) ! ! ILU(k) and MILU(k) ! select case(p%iprcparm(mld_sub_fill_in_)) case(:-1) ! Error: fill-in <= -1 call psb_errpush(30,name,i_err=(/3,p%iprcparm(mld_sub_fill_in_),0,0,0/)) goto 9999 case(0) ! Fill-in 0 ! Separate implementation of ILU(0) for better performance. ! There seems to be a problem with the separate implementation of MILU(0), ! contained into mld_ilu0_fact. This must be investigated. For the time being, ! resort to the implementation of MILU(k) with k=0. if (p%iprcparm(mld_sub_solve_) == mld_ilu_n_) then call mld_ilu0_fact(p%iprcparm(mld_sub_solve_),a,p%av(mld_l_pr_),p%av(mld_u_pr_),& & p%d,info,blck=blck) else call mld_iluk_fact(p%iprcparm(mld_sub_fill_in_),p%iprcparm(mld_sub_solve_),& & a,p%av(mld_l_pr_),p%av(mld_u_pr_),p%d,info,blck=blck) endif case(1:) ! Fill-in >= 1 ! The same routine implements both ILU(k) and MILU(k) call mld_iluk_fact(p%iprcparm(mld_sub_fill_in_),p%iprcparm(mld_sub_solve_),& & a,p%av(mld_l_pr_),p%av(mld_u_pr_),p%d,info,blck=blck) end select if (info/=0) then info=4010 ch_err='mld_iluk_fact' call psb_errpush(info,name,a_err=ch_err) goto 9999 end if case default ! If we end up here, something was wrong up in the call chain. call psb_errpush(4000,name) goto 9999 end select if (psb_sp_getifld(psb_upd_,p%av(mld_u_pr_),info) /= psb_upd_perm_) then call psb_sp_trim(p%av(mld_u_pr_),info) endif if (psb_sp_getifld(psb_upd_,p%av(mld_l_pr_),info) /= psb_upd_perm_) then call psb_sp_trim(p%av(mld_l_pr_),info) endif if (debug_level >= psb_debug_outer_) & & write(debug_unit,*) me,' ',trim(name),' end' call psb_erractionrestore(err_act) return 9999 continue call psb_erractionrestore(err_act) if (err_act.eq.psb_act_abort_) then call psb_error() return end if return end subroutine mld_dilu_bld