!!$ !!$ !!$ MLD2P4 version 1.1 !!$ MultiLevel Domain Decomposition Parallel Preconditioners Package !!$ based on PSBLAS (Parallel Sparse BLAS version 2.3.1) !!$ !!$ (C) Copyright 2008,2009 !!$ !!$ Salvatore Filippone University of Rome Tor Vergata !!$ Alfredo Buttari CNRS-IRIT, Toulouse !!$ Pasqua D'Ambra ICAR-CNR, Naples !!$ Daniela di Serafino Second University of Naples !!$ !!$ 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_sbaseprec_aply.f90 ! ! Subroutine: mld_sbaseprec_aply ! Version: real ! ! This routine applies a base preconditioner by computing ! ! Y = beta*Y + alpha*op(K^(-1))*X, ! where ! - K is the base preconditioner, stored in prec, ! - op(K^(-1)) is K^(-1) or its transpose, according to the value of trans, ! - X and Y are vectors, ! - alpha and beta are scalars. ! ! The routine is used by mld_smlprec_aply, to apply the multilevel preconditioners, ! or directly by mld_sprec_aply, to apply the basic one-level preconditioners (diagonal, ! block-Jacobi or additive Schwarz). It also manages the case of no preconditioning. ! ! ! Arguments: ! alpha - real(psb_spk_), input. ! The scalar alpha. ! prec - type(mld_sbaseprec_type), input. ! The base preconditioner data structure containing the local part ! of the preconditioner K. ! x - real(psb_spk_), dimension(:), input. ! The local part of the vector X. ! beta - real(psb_spk_), input. ! The scalar beta. ! y - real(psb_spk_), dimension(:), input/output. ! The local part of the vector Y. ! desc_data - type(psb_desc_type), input. ! The communication descriptor associated to the matrix to be ! preconditioned. ! trans - character, optional. ! If trans='N','n' then op(K^(-1)) = K^(-1); ! if trans='T','t' then op(K^(-1)) = K^(-T) (transpose of K^(-1)). ! work - real(psb_spk_), dimension (:), optional, target. ! Workspace. Its size must be at least 4*psb_cd_get_local_cols(desc_data). ! info - integer, output. ! Error code. ! subroutine mld_sbaseprec_aply(alpha,prec,x,beta,y,desc_data,trans,work,info) use psb_sparse_mod use mld_inner_mod, mld_protect_name => mld_sbaseprec_aply implicit none ! Arguments type(psb_desc_type),intent(in) :: desc_data type(mld_sbaseprec_type), intent(in) :: prec real(psb_spk_),intent(in) :: x(:) real(psb_spk_),intent(inout) :: y(:) real(psb_spk_),intent(in) :: alpha,beta character(len=1) :: trans real(psb_spk_),target :: work(:) integer, intent(out) :: info ! Local variables real(psb_spk_), pointer :: ww(:) integer :: ictxt, np, me, err_act integer :: n_row, int_err(5) character(len=20) :: name, ch_err character :: trans_ name='mld_sbaseprec_aply' info = psb_success_ call psb_erractionsave(err_act) ictxt = psb_cd_get_context(desc_data) call psb_info(ictxt, me, np) trans_= psb_toupper(trans) select case(trans_) case('N','T','C') ! Ok case default info=psb_err_iarg_invalid_i_ int_err(1)=6 ch_err(2:2)=trans goto 9999 end select select case(prec%iprcparm(mld_smoother_type_)) case(mld_noprec_) ! ! No preconditioner ! call psb_geaxpby(alpha,x,beta,y,desc_data,info) case(mld_diag_) ! ! Diagonal preconditioner ! if (size(work) >= size(x)) then ww => work else allocate(ww(size(x)),stat=info) if (info /= psb_success_) then call psb_errpush(psb_err_alloc_request_,name,i_err=(/size(x),0,0,0,0/),a_err='real(psb_spk_)') goto 9999 end if end if n_row = psb_cd_get_local_rows(desc_data) ww(1:n_row) = x(1:n_row)*prec%d(1:n_row) call psb_geaxpby(alpha,ww,beta,y,desc_data,info) if (size(work) < size(x)) then deallocate(ww,stat=info) if (info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='Deallocate') goto 9999 end if end if case(mld_bjac_,mld_as_) ! ! Additive Schwarz preconditioner (including block-Jacobi as special case) ! call mld_as_aply(alpha,prec,x,beta,y,desc_data,trans_,work,info) if(info /= psb_success_) then info=psb_err_from_subroutine_ ch_err='mld_as_aply' goto 9999 end if case default call psb_errpush(psb_err_internal_error_,name,a_err='Invalid mld_smoother_type_') goto 9999 end select call psb_erractionrestore(err_act) return 9999 continue call psb_errpush(info,name,i_err=int_err,a_err=ch_err) call psb_erractionrestore(err_act) if (err_act == psb_act_abort_) then call psb_error() return end if return end subroutine mld_sbaseprec_aply