simulation.f90

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module simulation
  use case
  use gather_scatter
  use time_scheme_controller
  use file
  use math
  use logger
  use device
  use device_math
  use jobctrl
  use field, only : field_t
  use profiler
  use math, only : col2
  use simcomp_executor, only : neko_simcomps
  use json_utils, only : json_get_or_default
  use time_step_controller
  implicit none
  private
 
  public :: neko_solve
 
contains
 
  subroutine neko_solve(C)
    type(case_t), target, intent(inout) :: c
    real(kind=rp) :: t, cfl
    real(kind=dp) :: start_time_org, start_time, end_time
    character(len=LOG_SIZE) :: log_buf
    integer :: tstep, i
    character(len=:), allocatable :: restart_file
    logical :: output_at_end, found
    ! for variable_tsteping
    real(kind=rp) :: cfl_avrg = 0.0_rp
    type(time_step_controller_t) :: dt_controller
 
    t = 0d0
    tstep = 0
    call neko_log%section('Starting simulation')
    write(log_buf,'(A, E15.7,A,E15.7,A)') 'T  : [', 0d0,',',c%end_time,')'
    call neko_log%message(log_buf)
    call dt_controller%init(c%params)
    if (.not. dt_controller%if_variable_dt) then
       write(log_buf,'(A, E15.7)') 'dt :  ', c%dt
       call neko_log%message(log_buf)
    else
       write(log_buf,'(A, E15.7)') 'CFL :  ', dt_controller%set_cfl
       call neko_log%message(log_buf)
    end if
 
    call c%params%get('case.restart_file', restart_file, found)
    if (found .and. len_trim(restart_file) .gt. 0) then
       ! Restart the case
       call simulation_restart(c, t)
 
       ! Restart the simulation components
       call neko_simcomps%restart(t)
    end if
 
    call neko_log%section('Postprocessing')
    call c%q%eval(t, c%dt, tstep)
    call c%s%sample(t, tstep)
 
    call c%usr%user_init_modules(t, c%fluid%u, c%fluid%v, c%fluid%w,&
                                 c%fluid%p, c%fluid%c_Xh, c%params)
    call neko_log%end_section()
    call neko_log%newline()
 
    call profiler_start
    cfl = c%fluid%compute_cfl(c%dt)
    start_time_org = mpi_wtime()
 
    do while (t .lt. c%end_time .and. (.not. jobctrl_time_limit()))
       call profiler_start_region('Time-Step')
       tstep = tstep + 1
       start_time = mpi_wtime()
       if (dt_controller%dt_last_change .eq. 0) then
          cfl_avrg = cfl
       end if
       call dt_controller%set_dt(c%dt, cfl, cfl_avrg, tstep)
       !calculate the cfl after the possibly varied dt
       cfl = c%fluid%compute_cfl(c%dt)
 
       call neko_log%status(t, c%end_time)
       write(log_buf, '(A,I6)') 'Time-step: ', tstep
       call neko_log%message(log_buf)
       call neko_log%begin()
 
       write(log_buf, '(A,E15.7,1x,A,E15.7)') 'CFL:', cfl, 'dt:', c%dt
       call neko_log%message(log_buf)
       call simulation_settime(t, c%dt, c%ext_bdf, c%tlag, c%dtlag, tstep)
 
       call neko_log%section('Fluid')
       call c%fluid%step(t, tstep, c%dt, c%ext_bdf, dt_controller)
       end_time = mpi_wtime()
       write(log_buf, '(A,E15.7,A,E15.7)') &
            'Elapsed time (s):', end_time-start_time_org, ' Step time:', &
            end_time-start_time
       call neko_log%end_section(log_buf)
 
       ! Scalar step
       if (allocated(c%scalar)) then
          start_time = mpi_wtime()
          call neko_log%section('Scalar')
          call c%scalar%step(t, tstep, c%dt, c%ext_bdf, dt_controller)
          end_time = mpi_wtime()
          write(log_buf, '(A,E15.7,A,E15.7)') &
               'Elapsed time (s):', end_time-start_time_org, ' Step time:', &
               end_time-start_time
          call neko_log%end_section(log_buf)
       end if
 
       call neko_log%section('Postprocessing')
       ! Execute all simulation components
       call neko_simcomps%compute(t, tstep)
 
       call c%q%eval(t, c%dt, tstep)
       call c%s%sample(t, tstep)
 
       ! Update material properties
       call c%usr%material_properties(t, tstep, c%material_properties%rho,&
                                      c%material_properties%mu, &
                                      c%material_properties%cp, &
                                      c%material_properties%lambda, &
                                      c%params)
 
       call c%usr%user_check(t, tstep,&
            c%fluid%u, c%fluid%v, c%fluid%w, c%fluid%p, c%fluid%c_Xh, c%params)
 
       call neko_log%end_section()
 
       call neko_log%end()
       call profiler_end_region
    end do
    call profiler_stop
 
    call json_get_or_default(c%params, 'case.output_at_end',&
                             output_at_end, .true.)
    call c%s%sample(t, tstep, output_at_end)
 
    if (.not. (output_at_end) .and. t .lt. c%end_time) then
       call simulation_joblimit_chkp(c, t)
    end if
 
    call c%usr%user_finalize_modules(t, c%params)
 
    call neko_log%end_section('Normal end.')
 
  end subroutine neko_solve
 
  subroutine simulation_settime(t, dt, ext_bdf, tlag, dtlag, step)
    real(kind=rp), intent(inout) :: t
    real(kind=rp), intent(in) :: dt
    type(time_scheme_controller_t), intent(inout) :: ext_bdf
    real(kind=rp), dimension(10) :: tlag
    real(kind=rp), dimension(10) :: dtlag
    integer, intent(in) :: step
    integer :: i
 
 
    do i = 10, 2, -1
       tlag(i) = tlag(i-1)
       dtlag(i) = dtlag(i-1)
    end do
 
    dtlag(1) = dt
    tlag(1) = t
    if (ext_bdf%ndiff .eq. 0) then
       dtlag(2) = dt
       tlag(2) = t
    end if
 
    t = t + dt
 
    call ext_bdf%set_coeffs(dtlag)
 
  end subroutine simulation_settime
 
  subroutine simulation_restart(C, t)
    implicit none
    type(case_t), intent(inout) :: C
    real(kind=rp), intent(inout) :: t
    integer :: i
    type(file_t) :: chkpf, previous_meshf
    character(len=LOG_SIZE) :: log_buf
    character(len=:), allocatable :: restart_file
    character(len=:), allocatable :: restart_mesh_file
    real(kind=rp) :: tol
    logical :: found
 
    call c%params%get('case.restart_file', restart_file, found)
    call c%params%get('case.restart_mesh_file', restart_mesh_file,&
                      found)
 
    if (found) then
       previous_meshf = file_t(trim(restart_mesh_file))
       call previous_meshf%read(c%fluid%chkp%previous_mesh)
    end if
 
    call c%params%get('case.mesh2mesh_tolerance', tol,&
                      found)
 
    if (found) c%fluid%chkp%mesh2mesh_tol = tol
    
    chkpf = file_t(trim(restart_file))
    call chkpf%read(c%fluid%chkp)
    c%dtlag = c%fluid%chkp%dtlag
    c%tlag = c%fluid%chkp%tlag
 
    !Free the previous mesh, dont need it anymore
    call c%fluid%chkp%previous_mesh%free()
    do i = 1, size(c%dtlag)
       call c%ext_bdf%set_coeffs(c%dtlag)
    end do
 
    call c%fluid%restart(c%dtlag, c%tlag)
    if (allocated(c%scalar)) call c%scalar%restart( c%dtlag, c%tlag)
 
    t = c%fluid%chkp%restart_time()
    call neko_log%section('Restarting from checkpoint')
    write(log_buf,'(A,A)') 'File :   ', &
         trim(restart_file)
    call neko_log%message(log_buf)
    write(log_buf,'(A,E15.7)') 'Time : ', t
    call neko_log%message(log_buf)
    call neko_log%end_section()
 
    call c%s%set_counter(t)
  end subroutine simulation_restart
 
  subroutine simulation_joblimit_chkp(C, t)
    type(case_t), intent(inout) :: C
    real(kind=rp), intent(inout) :: t
    type(file_t) :: chkpf
    character(len=LOG_SIZE) :: log_buf
 
    call c%fluid%chkp%sync_host()
    chkpf = file_t('joblimit.chkp')
    call chkpf%write(c%fluid%chkp, t)
    write(log_buf, '(A)') '! saving checkpoint >>>'
    call neko_log%message(log_buf)
 
  end subroutine simulation_joblimit_chkp
 
end module simulation