hecmw_precond_DIAG_11.f90

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!-------------------------------------------------------------------------------
! Copyright (c) 2019 FrontISTR Commons
! This software is released under the MIT License, see LICENSE.txt
!-------------------------------------------------------------------------------
 
!C
!C***
!C*** module hecmw_precond_DIAG_11
!C***
!C
module hecmw_precond_diag_11
  use  hecmw_util
 
  private
 
  public:: hecmw_precond_diag_11_setup
  public:: hecmw_precond_diag_11_apply
  public:: hecmw_precond_diag_11_clear
 
  integer(kind=kint) :: N
  real(kind=kreal), pointer :: alu(:) => null()
 
  logical, save :: INITIALIZED = .false.
 
contains
 
  subroutine hecmw_precond_diag_11_setup(hecMAT)
    use hecmw_matrix_misc
    implicit none
    type(hecmwst_matrix), intent(inout) :: hecmat
    integer(kind=kint ) :: np
    real   (kind=kreal) :: sigma_diag
    real(kind=kreal), pointer:: d(:)
 
    real   (kind=kreal):: alutmp(1,1), pw(1)
    integer(kind=kint ):: ii, i, j, k
 
    if (initialized) then
      if (hecmat%Iarray(98) == 0 .and. hecmat%Iarray(97) == 0) return
      call hecmw_precond_diag_11_clear()
    endif
 
    n = hecmat%N
    np = hecmat%NP
    d => hecmat%D
    sigma_diag = hecmw_mat_get_sigma_diag(hecmat)
 
    allocate(alu(np))
    alu = 0.d0
 
    do ii= 1, n
      alu(ii) = d(ii)
    enddo
 
    !$omp parallel default(none),private(ii,ALUtmp,k,i,j,PW),shared(N,ALU,SIGMA_DIAG)
    !$omp do
    do ii= 1, n
      alutmp(1,1)= alu(ii) * sigma_diag
      alutmp(1,1)= 1.d0/alutmp(1,1)
      alu(ii)= alutmp(1,1)
    enddo
    !$omp end do
    !$omp end parallel
 
    initialized = .true.
    hecmat%Iarray(98) = 0 ! symbolic setup done
    hecmat%Iarray(97) = 0 ! numerical setup done
 
  end subroutine hecmw_precond_diag_11_setup
 
  subroutine hecmw_precond_diag_11_apply(WW)
    implicit none
    real(kind=kreal), intent(inout) :: ww(:)
    integer(kind=kint) :: i
 
    !C
    !C== Block SCALING
 
    !$omp parallel default(none),private(i),shared(N,WW,ALU)
    !$omp do
    do i= 1, n
      ww(i)= alu(i)*ww(i)
    enddo
    !$omp end do
    !$omp end parallel
 
  end subroutine hecmw_precond_diag_11_apply
 
  subroutine hecmw_precond_diag_11_clear()
    implicit none
    if (associated(alu)) deallocate(alu)
    nullify(alu)
    initialized = .false.
  end subroutine hecmw_precond_diag_11_clear
 
end module     hecmw_precond_diag_11