!    This file is part of ELPA.
!
!    The ELPA library was originally created by the ELPA consortium,
!    consisting of the following organizations:
!
!    - Max Planck Computing and Data Facility (MPCDF), formerly known as
!      Rechenzentrum Garching der Max-Planck-Gesellschaft (RZG),
!    - Bergische Universität Wuppertal, Lehrstuhl für angewandte
!      Informatik,
!    - Technische Universität München, Lehrstuhl für Informatik mit
!      Schwerpunkt Wissenschaftliches Rechnen ,
!    - Fritz-Haber-Institut, Berlin, Abt. Theorie,
!    - Max-Plack-Institut für Mathematik in den Naturwissenschaften,
!      Leipzig, Abt. Komplexe Strukutren in Biologie und Kognition,
!      and
!    - IBM Deutschland GmbH
!
!
!    More information can be found here:
!    http://elpa.mpcdf.mpg.de/
!
!    ELPA is free software: you can redistribute it and/or modify
!    it under the terms of the version 3 of the license of the
!    GNU Lesser General Public License as published by the Free
!    Software Foundation.
!
!    ELPA 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 Lesser General Public License for more details.
!
!    You should have received a copy of the GNU Lesser General Public License
!    along with ELPA.  If not, see <http://www.gnu.org/licenses/>
!
!    ELPA reflects a substantial effort on the part of the original
!    ELPA consortium, and we ask you to respect the spirit of the
!    license that we chose: i.e., please contribute any changes you
!    may have back to the original ELPA library distribution, and keep
!    any derivatives of ELPA under the same license that we chose for
!    the original distribution, the GNU Lesser General Public License.
!
!
#include "config-f90.h"

#define stringify_(x) "x"
#define stringify(x) stringify_(x)
#define assert(x) call x_assert(x, stringify(x), __FILE__, __LINE__)

program test_interface
   use precision
   use assert
   use mod_setup_mpi
   use elpa_mpi
   use elpa_type
   use mod_prepare_matrix
   use mod_read_input_parameters
   use mod_blacs_infrastructure
   use mod_check_correctness

   implicit none

   ! matrix dimensions
   integer :: na, nev, nblk

   ! mpi
   integer :: myid, nprocs
   integer :: na_cols, na_rows  ! local matrix size
   integer :: np_cols, np_rows  ! number of MPI processes per column/row
   integer :: my_prow, my_pcol  ! local MPI task position (my_prow, my_pcol) in the grid (0..np_cols -1, 0..np_rows -1)
   integer :: mpierr

   ! blacs
   integer :: my_blacs_ctxt, sc_desc(9), info, nprow, npcol

   ! The Matrix
   real(kind=C_FLOAT_COMPLEX), allocatable :: a(:,:), as(:,:)
   ! eigenvectors
   real(kind=C_FLOAT_COMPLEX), allocatable :: z(:,:)
   ! eigenvalues
   real(kind=C_FLOAT), allocatable :: ev(:)

   integer :: success, status

   integer(kind=c_int) :: solver
   integer(kind=c_int) :: qr

   type(output_t) :: write_to_file
   type(elpa_t) :: e

   call read_input_parameters(na, nev, nblk, write_to_file)
   call setup_mpi(myid, nprocs)

   do np_cols = NINT(SQRT(REAL(nprocs))),2,-1
      if(mod(nprocs,np_cols) == 0 ) exit
   enddo

   np_rows = nprocs/np_cols

   my_prow = mod(myid, np_cols)
   my_pcol = myid / np_cols

   call set_up_blacsgrid(mpi_comm_world, my_blacs_ctxt, np_rows, np_cols, &
                         nprow, npcol, my_prow, my_pcol)

   call set_up_blacs_descriptor(na, nblk, my_prow, my_pcol, np_rows, np_cols, &
                                na_rows, na_cols, sc_desc, my_blacs_ctxt, info)

   allocate(a (na_rows,na_cols), as(na_rows,na_cols))
   allocate(z (na_rows,na_cols))
   allocate(ev(na))

   a(:,:) = 0.0
   z(:,:) = 0.0
   ev(:) = 0.0

   call prepare_matrix_single(na, myid, sc_desc, a, z, as)

   if (elpa_init(20170403) /= ELPA_OK) then
     error stop "ELPA API version not supported"
   endif

   e = elpa_create(na, nev, na_rows, na_cols, nblk, mpi_comm_world, my_prow, my_pcol, success)
   assert(success == ELPA_OK)

   qr = e%get("qr", success)
   print *, "qr =", qr
   assert(success == ELPA_OK)

   solver = e%get("solver", success)
   print *, "solver =", solver
   assert(success == ELPA_OK)

   call e%set("solver", ELPA_SOLVER_1STAGE, success)
   assert(success == ELPA_OK)

   call e%set("gpu", 1, success)
   assert(success == ELPA_OK)
 
   call e%set("complex_kernel", ELPA_2STAGE_COMPLEX_GENERIC, success)
   assert(success == ELPA_OK)

   call e%solve(a, ev, z, success)
   assert(success == ELPA_OK)

   call e%destroy()

   call elpa_uninit()

   status = check_correctness_single(na, nev, as, z, ev, sc_desc, myid)

   deallocate(a)
   deallocate(as)
   deallocate(z)
   deallocate(ev)

#ifdef WITH_MPI
   call mpi_finalize(mpierr)
#endif

end program