! ! Parallel Sparse BLAS version 3.5 ! (C) Copyright 2006-2018 ! Salvatore Filippone ! Alfredo Buttari ! ! Contributions to this routine: ! Daniela di Serafino Second University of Naples ! Pasqua D'Ambra ICAR-CNR ! ! 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. The name of the PSBLAS group or the names of its contributors may ! not be used to endorse or promote products derived from this ! software without specific written permission. ! ! THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ! ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ! TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR ! PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS ! BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR ! CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF ! SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS ! INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN ! CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ! ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ! POSSIBILITY OF SUCH DAMAGE. ! ! ! CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC ! C C ! C References: C ! C [1] Duff, I., Marrone, M., Radicati, G., and Vittoli, C. C ! C Level 3 basic linear algebra subprograms for sparse C ! C matrices: a user level interface C ! C ACM Trans. Math. Softw., 23(3), 379-401, 1997. C ! C C ! C C ! C [2] S. Filippone, M. Colajanni C ! C PSBLAS: A library for parallel linear algebra C ! C computation on sparse matrices C ! C ACM Trans. on Math. Softw., 26(4), 527-550, Dec. 2000. C ! C C ! C [3] M. Arioli, I. Duff, M. Ruiz C ! C Stopping criteria for iterative solvers C ! C SIAM J. Matrix Anal. Appl., Vol. 13, pp. 138-144, 1992 C ! C C ! C C ! C [4] R. Barrett et al C ! C Templates for the solution of linear systems C ! C SIAM, 1993 C ! C C ! C C ! C [5] G. Sleijpen, D. Fokkema C ! C BICGSTAB(L) for linear equations involving unsymmetric C ! C matrices with complex spectrum C ! C Electronic Trans. on Numer. Analysis, Vol. 1, pp. 11-32, C ! C Sep. 1993 C ! C C ! C C ! CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC ! File: psb_srgmres.f90 ! ! Subroutine: psb_srgmres ! This subroutine implements the restarted GMRES method with right ! preconditioning. ! ! Arguments: ! ! a - type(psb_sspmat_type) Input: sparse matrix containing A. ! prec - class(psb_sprec_type) Input: preconditioner ! b - real,dimension(:) Input: vector containing the ! right hand side B ! x - real,dimension(:) Input/Output: vector containing the ! initial guess and final solution X. ! eps - real Input: Stopping tolerance; the iteration is ! stopped when the error estimate |err| <= eps ! desc_a - type(psb_desc_type). Input: The communication descriptor. ! info - integer. Output: Return code ! ! itmax - integer(optional) Input: maximum number of iterations to be ! performed. ! iter - integer(optional) Output: how many iterations have been ! performed. ! performed. ! err - real (optional) Output: error estimate on exit. If the ! denominator of the estimate is exactly ! 0, it is changed into 1. ! itrace - integer(optional) Input: print an informational message ! with the error estimate every itrace ! iterations ! istop - integer(optional) Input: stopping criterion, or how ! to estimate the error. ! 1: err = |r|/(|a||x|+|b|); here the iteration is ! stopped when |r| <= eps * (|a||x|+|b|) ! 2: err = |r|/|b|; here the iteration is ! stopped when |r| <= eps * |b| ! where r is the (preconditioned, recursive ! estimate of) residual. ! irst - integer(optional) Input: restart parameter ! subroutine psb_srgmres_vect(a,prec,b,x,eps,desc_a,info,& & itmax,iter,err,itrace,irst,istop) use psb_base_mod use psb_prec_mod use psb_s_krylov_conv_mod use psb_krylov_mod implicit none type(psb_sspmat_type), intent(in) :: a Type(psb_desc_type), Intent(in) :: desc_a class(psb_sprec_type), intent(inout) :: prec type(psb_s_vect_type), Intent(inout) :: b type(psb_s_vect_type), Intent(inout) :: x Real(psb_spk_), Intent(in) :: eps integer(psb_ipk_), intent(out) :: info integer(psb_ipk_), Optional, Intent(in) :: itmax, itrace, irst,istop integer(psb_ipk_), Optional, Intent(out) :: iter Real(psb_spk_), Optional, Intent(out) :: err ! = local data real(psb_spk_), allocatable :: aux(:) real(psb_spk_), allocatable :: c(:), s(:), h(:,:), rs(:), rst(:) type(psb_s_vect_type), allocatable :: v(:) type(psb_s_vect_type) :: w, w1, xt real(psb_spk_) :: tmp real(psb_spk_) :: scal, gm, rti, rti1 integer(psb_ipk_) ::litmax, naux, it, k, itrace_,& & n_row, n_col, nl integer(psb_lpk_) :: mglob Logical, Parameter :: exchange=.True., noexchange=.False., use_srot=.true. integer(psb_ipk_), Parameter :: irmax = 8 integer(psb_ipk_) :: itx, i, istop_, err_act integer(psb_ipk_) :: debug_level, debug_unit integer(psb_ipk_) :: ictxt, np, me Real(psb_spk_) :: rni, xni, bni, ani,bn2, dt, r0n2 real(psb_dpk_) :: errnum, errden, deps, derr character(len=20) :: name character(len=*), parameter :: methdname='RGMRES' info = psb_success_ name = 'psb_sgmres' call psb_erractionsave(err_act) debug_unit = psb_get_debug_unit() debug_level = psb_get_debug_level() ictxt = desc_a%get_context() Call psb_info(ictxt, me, np) if (debug_level >= psb_debug_ext_)& & write(debug_unit,*) me,' ',trim(name),': from psb_info',np if (.not.allocated(b%v)) then info = psb_err_invalid_vect_state_ call psb_errpush(info,name) goto 9999 endif if (.not.allocated(x%v)) then info = psb_err_invalid_vect_state_ call psb_errpush(info,name) goto 9999 endif mglob = desc_a%get_global_rows() n_row = desc_a%get_local_rows() n_col = desc_a%get_local_cols() if (present(istop)) then istop_ = istop else istop_ = 2 endif ! ! ISTOP_ = 1: Normwise backward error, infinity norm ! ISTOP_ = 2: ||r||/||b||, 2-norm ! if ((istop_ < 1 ).or.(istop_ > 2 ) ) then info=psb_err_invalid_istop_ err=info call psb_errpush(info,name,i_err=(/istop_/)) goto 9999 endif if (present(itmax)) then litmax = itmax else litmax = 1000 endif if (present(itrace)) then itrace_ = itrace else itrace_ = 0 end if if (present(irst)) then nl = irst if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' present: irst: ',irst,nl else nl = 10 if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' not present: irst: ',irst,nl endif if (nl <=0 ) then info=psb_err_invalid_istop_ err=info call psb_errpush(info,name,i_err=(/nl/)) goto 9999 endif call psb_chkvect(mglob,lone,x%get_nrows(),lone,lone,desc_a,info) if(info /= psb_success_) then info=psb_err_from_subroutine_ call psb_errpush(info,name,a_err='psb_chkvect on X') goto 9999 end if call psb_chkvect(mglob,lone,b%get_nrows(),lone,lone,desc_a,info) if(info /= psb_success_) then info=psb_err_from_subroutine_ call psb_errpush(info,name,a_err='psb_chkvect on B') goto 9999 end if naux=4*n_col allocate(aux(naux),h(nl+1,nl+1),& &c(nl+1),s(nl+1),rs(nl+1), rst(nl+1),stat=info) if (info == psb_success_) call psb_geall(v,desc_a,info,n=nl+1) if (info == psb_success_) call psb_geall(w,desc_a,info) if (info == psb_success_) call psb_geall(w1,desc_a,info) if (info == psb_success_) call psb_geall(xt,desc_a,info) if (info == psb_success_) call psb_geasb(v,desc_a,info,mold=x%v) if (info == psb_success_) call psb_geasb(w,desc_a,info,mold=x%v) if (info == psb_success_) call psb_geasb(w1,desc_a,info,mold=x%v) if (info == psb_success_) call psb_geasb(xt,desc_a,info,mold=x%v) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Size of V,W,W1 ',v(1)%get_nrows(),size(v),& & w%get_nrows(),w1%get_nrows() if (istop_ == 1) then ani = psb_spnrmi(a,desc_a,info) bni = psb_geamax(b,desc_a,info) else if (istop_ == 2) then bn2 = psb_genrm2(b,desc_a,info) else if (istop_ == 3) then call psb_geaxpby(sone,b,szero,v(1),desc_a,info) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if call psb_spmm(-sone,a,x,sone,v(1),desc_a,info,work=aux) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if r0n2 = psb_genrm2(v(1),desc_a,info) endif errnum = szero errden = sone deps = eps if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if if ((itrace_ > 0).and.(me == 0)) call log_header(methdname) itx = 0 restart: do ! compute r0 = b-ax0 ! check convergence if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' restart: ',itx,it it = 0 call psb_geaxpby(sone,b,szero,v(1),desc_a,info) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if call psb_spmm(-sone,a,x,sone,v(1),desc_a,info,work=aux) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if rs(1) = psb_genrm2(v(1),desc_a,info) rs(2:) = szero if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if scal=sone/rs(1) ! rs(1) MIGHT BE VERY SMALL - USE DSCAL TO DEAL WITH IT? if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' on entry to amax: b: ',b%get_nrows(),rs(1),scal ! ! check convergence ! if (istop_ == 1) then rni = psb_geamax(v(1),desc_a,info) xni = psb_geamax(x,desc_a,info) errnum = rni errden = (ani*xni+bni) else if (istop_ == 2) then rni = psb_genrm2(v(1),desc_a,info) errnum = rni errden = bn2 else if (istop_ == 3) then rni = psb_genrm2(v(1),desc_a,info) errnum = rni errden = r0n2 endif if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if if (errnum <= eps*errden) exit restart if (itrace_ > 0) & & call log_conv(methdname,me,itx,itrace_,errnum,errden,deps) call v(1)%scal(scal) !v(1) = v(1) * scal if (itx >= litmax) exit restart ! ! inner iterations ! inner: Do i=1,nl itx = itx + 1 call prec%apply(v(i),w1,desc_a,info) call psb_spmm(sone,a,w1,szero,w,desc_a,info,work=aux) ! do k = 1, i h(k,i) = psb_gedot(v(k),w,desc_a,info) call psb_geaxpby(-h(k,i),v(k),sone,w,desc_a,info) end do h(i+1,i) = psb_genrm2(w,desc_a,info) scal=sone/h(i+1,i) call psb_geaxpby(scal,w,szero,v(i+1),desc_a,info) do k=2,i call srot(1,h(k-1,i),1,h(k,i),1,real(c(k-1),kind=psb_spk_),s(k-1)) enddo rti = h(i,i) rti1 = h(i+1,i) call srotg(rti,rti1,tmp,s(i)) c(i) = cmplx(tmp,szero) call srot(1,h(i,i),1,h(i+1,i),1,real(c(i),kind=psb_spk_),s(i)) h(i+1,i) = szero call srot(1,rs(i),1,rs(i+1),1,real(c(i),kind=psb_spk_),s(i)) if (istop_ == 1) then ! ! build x and then compute the residual and its infinity norm ! rst = rs call w1%set(szero) call strsm('l','u','n','n',i,1,sone,h,size(h,1),rst,size(rst,1)) if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Rebuild x-> RS:',rst(1:i) do k=1, i call psb_geaxpby(rst(k),v(k),sone,xt,desc_a,info) end do call prec%apply(xt,desc_a,info) call psb_geaxpby(sone,x,sone,xt,desc_a,info) call psb_geaxpby(sone,b,szero,w1,desc_a,info) call psb_spmm(-sone,a,xt,sone,w1,desc_a,info,work=aux) rni = psb_geamax(w1,desc_a,info) xni = psb_geamax(xt,desc_a,info) errnum = rni errden = (ani*xni+bni) ! else if (istop_ == 2) then ! ! compute the residual 2-norm as byproduct of the solution ! procedure of the least-squares problem ! rni = abs(rs(i+1)) errnum = rni errden = bn2 else if (istop_ == 3) then ! ! compute the residual 2-norm as byproduct of the solution ! procedure of the least-squares problem ! rni = abs(rs(i+1)) errnum = rni errden = r0n2 endif if (errnum <= eps*errden) then if (istop_ == 1) then call psb_geaxpby(sone,xt,szero,x,desc_a,info) ! = x = xt else if (istop_ == 2) then ! ! build x ! call strsm('l','u','n','n',i,1,sone,h,size(h,1),rs,size(rs,1)) if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Rebuild x-> RS:',rs(1:i) call w1%set(szero) do k=1, i call psb_geaxpby(rs(k),v(k),sone,w1,desc_a,info) end do call prec%apply(w1,w,desc_a,info) call psb_geaxpby(sone,w,sone,x,desc_a,info) end if exit restart end if if (itrace_ > 0) & & call log_conv(methdname,me,itx,itrace_,errnum,errden,deps) end do inner if (istop_ == 1) then call psb_geaxpby(sone,xt,szero,x,desc_a,info)! x = xt else if (istop_ == 2) then ! ! build x ! call strsm('l','u','n','n',nl,1,sone,h,size(h,1),rs,size(rs,1)) if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Rebuild x-> RS:',rs(1:nl) call w1%set(szero) do k=1, nl call psb_geaxpby(rs(k),v(k),sone,w1,desc_a,info) end do call prec%apply(w1,w,desc_a,info) call psb_geaxpby(sone,w,sone,x,desc_a,info) end if end do restart if (itrace_ > 0) & & call log_conv(methdname,me,itx,ione,errnum,errden,deps) call log_end(methdname,me,itx,errnum,errden,deps,err=derr,iter=iter) if (present(err)) err = derr if (info == psb_success_) call psb_gefree(v,desc_a,info) if (info == psb_success_) call psb_gefree(w,desc_a,info) if (info == psb_success_) call psb_gefree(w1,desc_a,info) if (info == psb_success_) call psb_gefree(xt,desc_a,info) if (info == psb_success_) deallocate(aux,h,c,s,rs,rst, stat=info) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 end if call psb_erractionrestore(err_act) return 9999 call psb_error_handler(err_act) return end subroutine psb_srgmres_vect