tensor4.f90

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module tensor4
  use neko_config, only : neko_bcknd_device
  use num_types, only : rp
  use device, only : device_map, device_unmap, device_memcpy, device_sync
  use math, only : cfill
  use device_math, only : device_copy, device_cfill
  use utils, only : neko_error, neko_varname_len
  use, intrinsic :: iso_c_binding
  implicit none
  private
 
  type, public :: tensor4_t
     real(kind=rp), allocatable :: x(:,:,:,:) 
     character(len=NEKO_VARNAME_LEN) :: name = ""
     type(c_ptr) :: x_d = c_null_ptr 
     integer, private :: n1 = 0
     integer, private :: n2 = 0
     integer, private :: n3 = 0
     integer, private :: n4 = 0
     integer, private :: n = 0
   contains
     procedure, pass(t), private :: init_dims => tensor4_init
     generic :: init => init_dims
     procedure, pass(t) :: free => tensor4_free
     procedure, pass(t) :: size => tensor4_size
     procedure, pass(t) :: copy_from => tensor4_copy_from
     procedure, pass(t) :: get_n1 => tensor4_n1
     procedure, pass(t) :: get_n2 => tensor4_n2
     procedure, pass(t) :: get_n3 => tensor4_n3
     procedure, pass(t) :: get_n4 => tensor4_n4
     procedure, pass(t) :: tensor4_assign_tensor4
     procedure, pass(t) :: tensor4_assign_scalar
 
     generic :: assignment(=) => tensor4_assign_tensor4, &
          tensor4_assign_scalar
 
     procedure, pass(t), private :: alloc => tensor4_allocate
  end type tensor4_t
 
  type, public :: tensor4_ptr_t
     type(tensor4_t), pointer :: ptr => null()
   contains
     procedure, pass(this) :: init => tensor4_ptr_init
     procedure, pass(this) :: free => tensor4_ptr_free
  end type tensor4_ptr_t
 
contains
 
  subroutine tensor4_init(t, n1, n2, n3, n4, name)
    class(tensor4_t), intent(inout) :: t
    integer, intent(in) :: n1
    integer, intent(in) :: n2
    integer, intent(in) :: n3
    integer, intent(in) :: n4
    character(len=*), intent(in), optional :: name
 
    ! t%alloc zeroes the device side (and synchronizes) before any
    ! host-side touch: under zero-copy the device then faults the
    ! pages first (device first touch), which gives contiguous
    ! physical mappings and thus better GPU TLB utilisation; rewriting
    ! the zeros on the host afterwards is benign.
    call t%alloc(n1, n2, n3, n4)
 
    if (present(name)) then
       t%name = name
    end if
 
  end subroutine tensor4_init
 
  subroutine tensor4_allocate(t, n1, n2, n3, n4)
    class(tensor4_t), intent(inout) :: t
    integer, intent(in) :: n1
    integer, intent(in) :: n2
    integer, intent(in) :: n3
    integer, intent(in) :: n4
 
    call t%free()
 
    allocate(t%x(n1, n2, n3, n4))
    t%n1 = n1
    t%n2 = n2
    t%n3 = n3
    t%n4 = n4
    t%n = n1*n2*n3*n4
 
    if (neko_bcknd_device .eq. 1) then
       call device_map(t%x, t%x_d, t%n)
       call device_cfill(t%x_d, 0.0_rp, t%n)
       call device_sync()
    end if
    call cfill(t%x, 0.0_rp, t%n)
 
  end subroutine tensor4_allocate
 
  subroutine tensor4_free(t)
    class(tensor4_t), intent(inout) :: t
 
    if (allocated(t%x)) then
       if (neko_bcknd_device .eq. 1) then
          call device_unmap(t%x, t%x_d)
       end if
       deallocate(t%x)
    end if
 
    t%n1 = 0
    t%n2 = 0
    t%n3 = 0
    t%n4 = 0
    t%n = 0
    t%name = ""
 
  end subroutine tensor4_free
 
  pure function tensor4_size(t) result(s)
    class(tensor4_t), intent(in) :: t
    integer :: s
    s = t%n
  end function tensor4_size
 
  subroutine tensor4_copy_from(t, memdir, sync)
    class(tensor4_t), intent(inout) :: t
    integer, intent(in) :: memdir
    logical, intent(in) :: sync
 
    if (neko_bcknd_device .eq. 1) then
       call device_memcpy(t%x, t%x_d, t%n, memdir, sync)
    end if
 
  end subroutine tensor4_copy_from
 
  pure function tensor4_n1(t) result(n1)
    class(tensor4_t), intent(in) :: t
    integer :: n1
    n1 = t%n1
  end function tensor4_n1
 
  pure function tensor4_n2(t) result(n2)
    class(tensor4_t), intent(in) :: t
    integer :: n2
    n2 = t%n2
  end function tensor4_n2
 
  pure function tensor4_n3(t) result(n3)
    class(tensor4_t), intent(in) :: t
    integer :: n3
    n3 = t%n3
  end function tensor4_n3
 
  pure function tensor4_n4(t) result(n4)
    class(tensor4_t), intent(in) :: t
    integer :: n4
    n4 = t%n4
  end function tensor4_n4
 
  subroutine tensor4_assign_tensor4(t, w)
    class(tensor4_t), intent(inout) :: t
    type(tensor4_t), intent(in) :: w
 
    if (allocated(t%x)) then
       call t%free()
    end if
 
    if (.not. allocated(t%x)) then
 
       t%n1 = w%n1
       t%n2 = w%n2
       t%n3 = w%n3
       t%n4 = w%n4
       t%n = w%n
       allocate(t%x(t%n1, t%n2, t%n3, t%n4))
 
       if (neko_bcknd_device .eq. 1) then
          call device_map(t%x, t%x_d, t%n)
       end if
 
    end if
 
    if (neko_bcknd_device .eq. 1) then
       call device_copy(t%x_d, w%x_d, t%n)
    else
       t%x = w%x
    end if
 
    t%name = w%name
 
  end subroutine tensor4_assign_tensor4
 
  subroutine tensor4_assign_scalar(t, s)
    class(tensor4_t), intent(inout) :: t
    real(kind=rp), intent(in) :: s
 
    if (.not. allocated(t%x)) then
       call neko_error('tensor4 not allocated')
    end if
 
    if (neko_bcknd_device .eq. 1) then
       call device_cfill(t%x_d, s, t%n)
    else
       t%x = s
    end if
 
  end subroutine tensor4_assign_scalar
 
  ! ========================================================================== !
  ! tensor4 pointer type subroutines
 
  subroutine tensor4_ptr_init(this, ptr)
    class(tensor4_ptr_t), intent(inout) :: this
    type(tensor4_t), target, intent(in) :: ptr
 
    call this%free()
    this%ptr => ptr
  end subroutine tensor4_ptr_init
 
  subroutine tensor4_ptr_free(this)
    class(tensor4_ptr_t), intent(inout) :: this
 
    if (associated(this%ptr)) then
       nullify(this%ptr)
    end if
 
  end subroutine tensor4_ptr_free
 
end module tensor4