amg4psblas/mlprec/mld_dprecinit.f90

!!$ 
!!$ 
!!$                           MLD2P4  version 1.0
!!$  MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$             based on PSBLAS (Parallel Sparse BLAS version 2.2)
!!$  
!!$  (C) Copyright 2008
!!$
!!$                      Salvatore Filippone  University of Rome Tor Vergata       
!!$                      Alfredo Buttari      University of Rome Tor Vergata
!!$                      Pasqua D'Ambra       ICAR-CNR, Naples
!!$                      Daniela di Serafino  Second University of Naples
!!$ 
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! File: mld_dprecinit.f90
!
! Subroutine: mld_dprecinit
! Version:    real
!
!  This routine allocates and initializes the preconditioner data structure,
!  according to the preconditioner type chosen by the user.
!  
!  A default preconditioner is set for each preconditioner type
!  specified by the user:
!
!    'NONE', 'NOPREC' - no preconditioner
!
!    'DIAG'           - diagonal preconditioner
!
!    'BJAC'           - block Jacobi preconditioner, with ILU(0)
!                       on the local blocks
!
!    'AS'             - Restricted Additive Schwarz (RAS), with
!                       overlap 1 and ILU(0) on the local submatrices
!
!    'ML'             - Multilevel hybrid preconditioner (additive on the
!                       same level and multiplicative through the levels),
!                       with nlev levels and post-smoothing only. The block
!                       Jacobi preconditioner, with ILU(0) on the local
!                       blocks, is applied as post-smoother at each level
!                       but the coarsest one; four sweeps of the block-Jacobi
!                       solver, with ILU(0) on the blocks, are applied at
!                       the coarsest level, on the distributed coarse matrix. 
!
!  For the multilevel preconditioners, the levels are numbered in increasing
!  order starting from the finest one, i.e. level 1 is the finest level. 
!
!
! Arguments:
!    p       -  type(mld_dprec_type), input/output.
!               The preconditioner data structure.
!    ptype   -  character(len=*), input.
!               The type of preconditioner. Its values are 'NONE',
!               'NOPREC', 'DIAG', 'BJAC', 'AS', 'ML' (and the corresponding
!               lowercase strings).
!    info    -  integer, output.
!               Error code.
!    nlev    -  integer, optional, input.
!               The number of levels of the multilevel preconditioner.
!               If nlev is not present and ptype='ML', then nlev=2
!               is assumed. If ptype/='ML', nlev is ignored.
!  
subroutine mld_dprecinit(p,ptype,info,nlev)

  use psb_base_mod
  use mld_prec_mod, mld_protect_name => mld_dprecinit

  implicit none

! Arguments
  type(mld_dprec_type), intent(inout)    :: p
  character(len=*), intent(in)           :: ptype
  integer, intent(out)                   :: info
  integer, optional, intent(in)          :: nlev

! Local variables
  integer                                :: nlev_, ilev_
  character(len=*), parameter            :: name='mld_precinit'
  info = 0
  
  if (allocated(p%baseprecv)) then 
    call mld_precfree(p,info) 
    if (info /=0) then 
      ! Do we want to do something? 
    endif
  endif

  select case(psb_toupper(ptype(1:len_trim(ptype))))
  case ('NONE','NOPREC') 
    nlev_ = 1
    ilev_ = 1
    allocate(p%baseprecv(nlev_),stat=info) 
    if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
    if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
    if (info /= 0) return
    p%baseprecv(ilev_)%iprcparm(:) = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)     = mld_noprec_
    p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)     = mld_f_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)     = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)      = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)       = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)         = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_) = 1

  case ('DIAG')
    nlev_ = 1
    ilev_ = 1
    allocate(p%baseprecv(nlev_),stat=info) 
    if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
    if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
    if (info /= 0) return
    p%baseprecv(ilev_)%iprcparm(:)              = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)     = mld_diag_
    p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)     = mld_f_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)     = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)      = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)       = 0 
    p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)         = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_) = 1

  case ('BJAC') 
    nlev_ = 1
    ilev_ = 1
    allocate(p%baseprecv(nlev_),stat=info) 
    if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
    if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
    if (info /= 0) return
    p%baseprecv(ilev_)%iprcparm(:)              = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)     = mld_bjac_
    p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)     = mld_ilu_n_
    p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)     = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)      = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)       = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)         = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_fillin_)   = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_) = 1

  case ('AS')
    nlev_ = 1
    ilev_ = 1
    allocate(p%baseprecv(nlev_),stat=info) 
    if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
    if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
    if (info /= 0) return
    p%baseprecv(ilev_)%iprcparm(:)               = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)      = mld_as_ 
    p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)      = mld_ilu_n_
    p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)      = psb_halo_
    p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)       = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)        = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)          = 1
    p%baseprecv(ilev_)%iprcparm(mld_sub_fillin_)    = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_)  = 1


  case ('ML')
    
    if (present(nlev)) then 
      nlev_ = max(1,nlev)
    else
      nlev_ = 2
    end if
    ilev_ = 1
    allocate(p%baseprecv(nlev_),stat=info) 
    if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
    if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
    if (info /= 0) return
    p%baseprecv(ilev_)%iprcparm(:)                   = 0
    p%baseprecv(ilev_)%rprcparm(:)                   = dzero
    p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)      = mld_as_ 
    p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)      = mld_ilu_n_
    p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)      = psb_halo_
    p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)       = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)        = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)          = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_fillin_)    = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_)  = 1
    if (nlev_ == 1) return 

    do ilev_ = 2, nlev_ -1 
      if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
      if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
      if (info /= 0) return
      p%baseprecv(ilev_)%iprcparm(:)                  = 0
      p%baseprecv(ilev_)%rprcparm(:)                  = dzero
      p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)     = mld_bjac_
      p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)     = psb_none_
      p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)      = psb_none_
      p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)       = 0
      p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)         = 0
      p%baseprecv(ilev_)%iprcparm(mld_ml_type_)       = mld_mult_ml_
      p%baseprecv(ilev_)%iprcparm(mld_aggr_alg_)      = mld_dec_aggr_
      p%baseprecv(ilev_)%iprcparm(mld_aggr_kind_)     = mld_smooth_prol_
      p%baseprecv(ilev_)%iprcparm(mld_coarse_mat_)    = mld_distr_mat_
      p%baseprecv(ilev_)%iprcparm(mld_smoother_pos_)    = mld_post_smooth_
      p%baseprecv(ilev_)%iprcparm(mld_aggr_eig_)      = mld_max_norm_
      p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)     = mld_ilu_n_
      p%baseprecv(ilev_)%iprcparm(mld_sub_fillin_)   = 0
      p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_) = 1
      p%baseprecv(ilev_)%rprcparm(mld_aggr_damp_)     = 4.d0/3.d0         
    end do
    ilev_ = nlev_
    if (info == 0) call psb_realloc(mld_ifpsz_,p%baseprecv(ilev_)%iprcparm,info)
    if (info == 0) call psb_realloc(mld_rfpsz_,p%baseprecv(ilev_)%rprcparm,info)
    if (info /= 0) return
    p%baseprecv(ilev_)%iprcparm(:)                  = 0
    p%baseprecv(ilev_)%rprcparm(:)                  = dzero
    p%baseprecv(ilev_)%iprcparm(mld_smoother_type_)     = mld_bjac_
    p%baseprecv(ilev_)%iprcparm(mld_sub_restr_)     = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_prol_)      = psb_none_
    p%baseprecv(ilev_)%iprcparm(mld_sub_ren_)       = 0
    p%baseprecv(ilev_)%iprcparm(mld_sub_ovr_)         = 0
    p%baseprecv(ilev_)%iprcparm(mld_ml_type_)       = mld_mult_ml_
    p%baseprecv(ilev_)%iprcparm(mld_aggr_alg_)      = mld_dec_aggr_
    p%baseprecv(ilev_)%iprcparm(mld_aggr_kind_)     = mld_smooth_prol_
    p%baseprecv(ilev_)%iprcparm(mld_coarse_mat_)    = mld_distr_mat_
    p%baseprecv(ilev_)%iprcparm(mld_smoother_pos_)    = mld_post_smooth_
    p%baseprecv(ilev_)%iprcparm(mld_aggr_eig_)      = mld_max_norm_
    p%baseprecv(ilev_)%iprcparm(mld_sub_solve_)     = mld_ilu_n_
    p%baseprecv(ilev_)%iprcparm(mld_sub_fillin_)   = 0
    p%baseprecv(ilev_)%iprcparm(mld_smoother_sweeps_) = 4
    p%baseprecv(ilev_)%rprcparm(mld_aggr_damp_)     = 4.d0/3.d0         

  case default
    write(0,*) name,': Warning: Unknown preconditioner type request "',ptype,'"'
    info = 2

  end select


end subroutine mld_dprecinit