!>
!> @file transfer1d_col.f90
!>
!> @brief
!>
!> @copyright
!> Copyright (©) 2021 EPFL (Ecole Polytechnique Fédérale de Lausanne)
!> SPC (Swiss Plasma Center)
!>
!> SPClibs is free software: you can redistribute it and/or modify it under
!> the terms of the GNU Lesser General Public License as published by the Free
!> Software Foundation, either version 3 of the License, or (at your option)
!> any later version.
!>
!> SPClibs is distributed in the hope that it will be useful, but WITHOUT ANY
!> WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
!> FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
!>
!> You should have received a copy of the GNU Lesser General Public License
!> along with this program. If not, see <https://www.gnu.org/licenses/>.
!>
!> @authors
!> (in alphabetical order)
!> @author Trach-Minh Tran <trach-minh.tran@epfl.ch>
!>
PROGRAM main
!
!    Obtain grid transfer by collocation
!
  USE multigrid
  IMPLICIT NONE
!
  INTEGER :: nx=8, nidbas=1
  LOGICAL :: nlper=.TRUE.
!
  TYPE(grid1d) :: gridx(2)
  TYPE(gemat)  :: pmat
!
  NAMELIST /newrun/ nx, nidbas, nlper
!--------------------------------------------------------------------------------
  READ(*,newrun)
  WRITE(*,newrun)
!
  CALL create_grid(nx, nidbas, 1, 0, gridx, period=nlper)
  CALL printmat('** Prolongation matrix (using mass matrix) **', gridx(2)%transf)
!
  CALL calc_pmat(gridx(1), gridx(2), pmat, .TRUE.)
  CALL printmat('** Prolongation matrix (by collocation) **', pmat)
!
  WRITE(*,'(/a,1pe12.3)') 'Max diff =', MAXVAL(ABS(pmat%val-gridx(2)%transf%val))
!
END PROGRAM main