amg4psblas/samples/advanced/pdegen/amg_d_pde2d_poisson_mod.f90

!
!
!                             AMG4PSBLAS version 1.0
!    Algebraic Multigrid Package
!               based on PSBLAS (Parallel Sparse BLAS version 3.7)
!
!    (C) Copyright 2021
!
!        Salvatore Filippone
!        Pasqua D'Ambra
!        Fabio Durastante
!
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module amg_d_pde2d_poisson_mod
  use psb_base_mod, only : psb_dpk_, dzero, done
  real(psb_dpk_), save, private :: epsilon=done/80
contains
  subroutine pde_set_parm2d_poisson(dat)
    real(psb_dpk_), intent(in) :: dat
    epsilon = dat
  end subroutine pde_set_parm2d_poisson
  !
  ! functions parametrizing the differential equation
  !
  function b1_poisson(x,y)
    implicit none 
    real(psb_dpk_) :: b1_poisson
    real(psb_dpk_), intent(in) :: x,y
    b1_poisson = dzero
  end function b1_poisson
  function b2_poisson(x,y)
    implicit none 
    real(psb_dpk_) ::  b2_poisson
    real(psb_dpk_), intent(in) :: x,y
    b2_poisson = dzero
  end function b2_poisson
  function c_poisson(x,y)
    implicit none 
    real(psb_dpk_) ::  c_poisson
    real(psb_dpk_), intent(in) :: x,y
    c_poisson = dzero
  end function c_poisson
  function a1_poisson(x,y)
    implicit none 
    real(psb_dpk_) ::  a1_poisson
    real(psb_dpk_), intent(in) :: x,y
    a1_poisson=done*epsilon
  end function a1_poisson
  function a2_poisson(x,y)
    implicit none 
    real(psb_dpk_) ::  a2_poisson
    real(psb_dpk_), intent(in) :: x,y
    a2_poisson=done*epsilon
  end function a2_poisson
  function g_poisson(x,y)
    implicit none 
    real(psb_dpk_) ::  g_poisson
    real(psb_dpk_), intent(in) :: x,y
    g_poisson = dzero
    if (x == done) then
      g_poisson = done
    else if (x == dzero) then
      g_poisson = done
    end if
  end function g_poisson
end module amg_d_pde2d_poisson_mod