!!$ !!$ Parallel Sparse BLAS version 3.0 !!$ (C) Copyright 2006, 2007, 2008, 2009, 2010 !!$ Salvatore Filippone University of Rome Tor Vergata !!$ Alfredo Buttari CNRS-IRIT, Toulouse !!$ !!$ 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 !!$ CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC ! File: psb_scgstab.f90 ! ! Subroutine: psb_scgstab ! This subroutine implements the BiCG Stabilized method. ! ! ! 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. ! 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|/|b|; here the iteration is ! stopped when |r| <= eps * |b| ! 2: err = |r|/(|a||x|+|b|); here the iteration is ! stopped when |r| <= eps * (|a||x|+|b|) ! where r is the (preconditioned, recursive ! estimate of) residual. ! ! ! Subroutine psb_scgstab(a,prec,b,x,eps,desc_a,info,itmax,iter,err,itrace,istop) use psb_base_mod use psb_prec_mod use psb_inner_krylov_mod use psb_krylov_mod Implicit None !!$ parameters Type(psb_sspmat_type), Intent(in) :: a class(psb_sprec_type), Intent(in) :: prec Type(psb_desc_type), Intent(in) :: desc_a Real(psb_spk_), Intent(in) :: b(:) Real(psb_spk_), Intent(inout) :: x(:) Real(psb_spk_), Intent(in) :: eps integer, intent(out) :: info Integer, Optional, Intent(in) :: itmax, itrace, istop Integer, Optional, Intent(out) :: iter Real(psb_spk_), Optional, Intent(out) :: err !!$ Local data Real(psb_spk_), allocatable, target :: aux(:),wwrk(:,:) Real(psb_spk_), Pointer :: q(:),& & r(:), p(:), v(:), s(:), t(:), z(:), f(:) Integer :: itmax_, naux, mglob, it,itrace_,& & np,me, n_row, n_col integer :: debug_level, debug_unit Logical, Parameter :: exchange=.True., noexchange=.False., debug1 = .False. Integer, Parameter :: irmax = 8 Integer :: itx, isvch, ictxt, err_act Integer :: istop_ real(psb_dpk_) :: derr Real(psb_spk_) :: alpha, beta, omega Real(psb_dpk_) :: rho, rho_old, sigma, tau type(psb_itconv_type) :: stopdat #ifdef MPE_KRYLOV Integer istpb, istpe, ifctb, ifcte, imerr, irank, icomm,immb,imme Integer mpe_log_get_event_number,mpe_Describe_state,mpe_log_event #endif character(len=20) :: name character(len=*), parameter :: methdname='BiCGStab' info = psb_success_ name = 'psb_scgstab' 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 #ifdef MPE_KRYLOV call psb_get_mpicomm(ictxt,icomm) call psb_get_rank(irank,ictxt,me) istpb = mpe_log_get_event_number() istpe = mpe_log_get_event_number() ifctb = mpe_log_get_event_number() ifcte = mpe_log_get_event_number() immb = mpe_log_get_event_number() imme = mpe_log_get_event_number() if (irank == 0) then info = mpe_describe_state(istpb,istpe,"Solver","WhiteSmoke") info = mpe_describe_state(ifctb,ifcte,"PREC","SteelBlue") info = mpe_describe_state(immb,imme,"SPMM","DarkOrange") endif #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|| norm 2 ! #ifdef MPE_KRYLOV imerr = MPE_Log_event( istpb, 0, "st CGSTAB" ) #endif call psb_chkvect(mglob,1,size(x,1),1,1,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,1,size(b,1),1,1,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=6*n_col allocate(aux(naux),stat=info) if (info == psb_success_) call psb_geall(wwrk,desc_a,info,n=8) if (info == psb_success_) call psb_geasb(wwrk,desc_a,info) if (info /= psb_success_) then info=psb_err_from_subroutine_non_ call psb_errpush(info,name) goto 9999 End If Q => WWRK(:,1) R => WWRK(:,2) P => WWRK(:,3) V => WWRK(:,4) F => WWRK(:,5) S => WWRK(:,6) T => WWRK(:,7) Z => WWRK(:,8) If (Present(itmax)) Then itmax_ = itmax Else itmax_ = 1000 Endif If (Present(itrace)) Then itrace_ = itrace Else itrace_ = 0 End If ! Ensure global coherence for convergence checks. call psb_set_coher(ictxt,isvch) itx = 0 call psb_init_conv(methdname,istop_,itrace_,itmax_,a,b,eps,desc_a,stopdat,info) if (info /= psb_success_) Then call psb_errpush(psb_err_from_subroutine_non_,name) goto 9999 End If restart: Do if (itx >= itmax_) exit restart it = 0 call psb_geaxpby(sone,b,szero,r,desc_a,info) #ifdef MPE_KRYLOV imerr = MPE_Log_event( immb, 0, "st SPMM" ) #endif if (info == psb_success_) call psb_spmm(-sone,a,x,sone,r,desc_a,info,work=aux) #ifdef MPE_KRYLOV imerr = MPE_Log_event( imme, 0, "ed SPMM" ) #endif if (info == psb_success_) call psb_geaxpby(sone,r,szero,q,desc_a,info) if (info /= psb_success_) then info=psb_err_from_subroutine_ call psb_errpush(info,name,a_err='Init residual') goto 9999 end if ! Perhaps we already satisfy the convergence criterion... if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart if (info /= psb_success_) Then call psb_errpush(psb_err_from_subroutine_non_,name) goto 9999 End If rho = szero iteration: Do it = it + 1 itx = itx + 1 if (debug_level >= psb_debug_ext_)& & write(debug_unit,*) me,' ',trim(name),& & ' Iteration: ',itx rho_old = rho rho = psb_gedot(q,r,desc_a,info) if (rho == szero) then if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Iteration breakdown R',rho exit iteration endif if (it == 1) then call psb_geaxpby(sone,r,szero,p,desc_a,info) else beta = (rho/rho_old)*(alpha/omega) call psb_geaxpby(-omega,v,sone,p,desc_a,info) call psb_geaxpby(sone,r,beta,p,desc_a,info) End If #ifdef MPE_KRYLOV imerr = MPE_Log_event( ifctb, 0, "st PREC" ) #endif call prec%apply(p,f,desc_a,info,work=aux) #ifdef MPE_KRYLOV imerr = MPE_Log_event( ifcte, 0, "ed PREC" ) imerr = MPE_Log_event( immb, 0, "st SPMM" ) #endif call psb_spmm(sone,a,f,szero,v,desc_a,info,& & work=aux) #ifdef MPE_KRYLOV imerr = MPE_Log_event( imme, 0, "ed SPMM" ) #endif sigma = psb_gedot(q,v,desc_a,info) if (sigma == szero) then if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Iteration breakdown S1', sigma exit iteration endif alpha = rho/sigma call psb_geaxpby(sone,r,szero,s,desc_a,info) if (info == psb_success_) call psb_geaxpby(-alpha,v,sone,s,desc_a,info) if(info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='psb_geaxpby') goto 9999 end if #ifdef MPE_KRYLOV imerr = MPE_Log_event( ifctb, 0, "st PREC" ) #endif call prec%apply(s,z,desc_a,info,work=aux) #ifdef MPE_KRYLOV imerr = MPE_Log_event( ifcte, 0, "ed PREC" ) imerr = MPE_Log_event( immb, 0, "st SPMM" ) #endif if (info == psb_success_) Call psb_spmm(sone,a,z,szero,t,desc_a,info,& & work=aux) #ifdef MPE_KRYLOV imerr = MPE_Log_event( imme, 0, "ed SPMM" ) #endif if(info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='precaply/spmm') goto 9999 end if sigma = psb_gedot(t,t,desc_a,info) if (sigma == szero) then if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Iteration breakdown S2', sigma exit iteration endif tau = psb_gedot(t,s,desc_a,info) omega = tau/sigma if (omega == szero) then if (debug_level >= psb_debug_ext_) & & write(debug_unit,*) me,' ',trim(name),& & ' Iteration breakdown O',omega exit iteration endif call psb_geaxpby(alpha,f,sone,x,desc_a,info) if (info == psb_success_) call psb_geaxpby(omega,z,sone,x,desc_a,info) if (info == psb_success_) call psb_geaxpby(sone,s,szero,r,desc_a,info) if (info == psb_success_) call psb_geaxpby(-omega,t,sone,r,desc_a,info) if (info /= psb_success_) Then call psb_errpush(psb_err_from_subroutine_,name,a_err='X/R update ') goto 9999 End If if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart if (info /= psb_success_) Then call psb_errpush(psb_err_from_subroutine_non_,name) goto 9999 End If end do iteration end do restart call psb_end_conv(methdname,itx,desc_a,stopdat,info,derr,iter) if (present(err)) then err = derr end if deallocate(aux,stat=info) if (info == psb_success_) call psb_gefree(wwrk,desc_a,info) if(info /= psb_success_) then call psb_errpush(info,name) goto 9999 end if #ifdef MPE_KRYLOV imerr = MPE_Log_event( istpe, 0, "ed CGSTAB" ) #endif ! restore external global coherence behaviour call psb_restore_coher(ictxt,isvch) call psb_erractionrestore(err_act) return 9999 continue call psb_erractionrestore(err_act) if (err_act == psb_act_abort_) then call psb_error(ictxt) return end if return End Subroutine psb_scgstab