time_interpolator.f90

Go to the documentation of this file.

! Copyright (c) 2022-2025, The Neko Authors
! All rights reserved.
!
! Redistribution and use in source and binary forms, with or without
! modification, are permitted provided that the following conditions
! are met:
!
!   * Redistributions of source code must retain the above copyright
!     notice, this list of conditions and the following disclaimer.
!
!   * Redistributions in binary form must reproduce the above
!     copyright notice, this list of conditions and the following
!     disclaimer in the documentation and/or other materials provided
!     with the distribution.
!
!   * Neither the name of the authors nor the names of its
!     contributors may be used to endorse or promote products derived
!     from this software without specific prior written permission.
!
! THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
! "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
! LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
! FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
! COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
! INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
! BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
! LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
! CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
! ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
! POSSIBILITY OF SUCH DAMAGE.
!
module time_interpolator
  use num_types, only : rp
  use field, only : field_t
  use neko_config, only : neko_bcknd_device
  use device_math, only : device_add3s2
  use math, only : add3s2, rzero
  use utils, only : neko_error
  use, intrinsic :: iso_c_binding
  use fast3d, only : fd_weights_full
  implicit none
  private
 
  type, public :: time_interpolator_t
     integer :: order
   contains
     procedure, pass(this) :: init => time_interpolator_init
     procedure, pass(this) :: free => time_interpolator_free
     procedure, pass(this) :: interpolate => time_interpolator_interpolate
     procedure, pass(this) :: interpolate_scalar => time_interpolator_scalar
 
  end type time_interpolator_t
 
contains
 
  subroutine time_interpolator_init(this, order)
    class(time_interpolator_t), intent(inout) :: this
    integer, intent(in), target :: order
 
    call this%free()
 
    this%order = order
 
  end subroutine time_interpolator_init
 
 
  subroutine time_interpolator_free(this)
    class(time_interpolator_t), intent(inout) :: this
 
  end subroutine time_interpolator_free
 
  subroutine time_interpolator_interpolate(this, t, f, t_past, f_past, &
       t_future, f_future)
    class(time_interpolator_t), intent(inout) :: this
    real(kind=rp), intent(inout) :: t, t_past, t_future
    type(field_t), intent(inout) :: f, f_past, f_future
    real(kind=rp) :: w_past, w_future !Weights for the interpolation
    integer :: n
 
    if (this%order .eq. 2) then
 
       n = f%dof%size()
       w_past = ( t_future - t ) / ( t_future - t_past )
       w_future = ( t - t_past ) / ( t_future - t_past )
 
       if (neko_bcknd_device .eq. 1) then
          call device_add3s2(f%x_d, f_past%x_d, f_future%x_d, &
               w_past, w_future, n)
       else
          call add3s2(f%x, f_past%x, f_future%x, w_past, w_future, n)
       end if
 
    else
       call neko_error("Time interpolation of required order &
       &is not implemented")
    end if
 
  end subroutine time_interpolator_interpolate
 
  subroutine time_interpolator_scalar(this, t, f_interpolated, f_n, tlag, n)
    class(time_interpolator_t), intent(inout) :: this
    real(kind=rp), intent(in) :: t
    integer, intent(in) :: n
    real(kind=rp), dimension(n, 0:this%order - 1), intent(in) :: f_n
    real(kind=rp), dimension(n), intent(inout) :: f_interpolated
    real(kind=rp), dimension(0:this%order), intent(in) :: tlag
    integer :: no, i, l
 
 
    real(kind=rp), dimension(0:this%order + 1) :: wt
    wt = 0
 
 
    no = this%order - 1
    call fd_weights_full(t, tlag, no, 0, wt) ! interpolation weights
 
    if (neko_bcknd_device .eq. 1) then
       call neko_error('no device backend configured')
    else
       do concurrent(i = 1:n)
          f_interpolated(i) = wt(0) * f_n(i, 0)
          do l = 1, no
             f_interpolated(i) = f_interpolated(i) + wt(l) * f_n(i, l)
          end do
       end do
    end if
 
  end subroutine time_interpolator_scalar
 
end module time_interpolator