torch_model_forward Subroutine

  subroutine torch_model_forward(model, input_tensors, output_tensors, requires_grad)
    use, intrinsic :: iso_c_binding, only : c_bool, c_ptr, c_int, c_loc
    type(torch_model), intent(in) :: model  !! Model
    type(torch_tensor), intent(in), dimension(:) :: input_tensors   !! Array of Input tensors
    type(torch_tensor), intent(in), dimension(:) :: output_tensors  !! Returned output tensors
    logical, optional, intent(in) :: requires_grad  !! Whether gradients need to be computed for the created tensor
    logical :: requires_grad_value  !! Whether gradients need to be computed for the created tensor

    integer(ftorch_int) :: i
    integer(c_int)      :: n_inputs
    integer(c_int)      :: n_outputs
    type(c_ptr), dimension(size(input_tensors)), target  :: input_ptrs
    type(c_ptr), dimension(size(output_tensors)), target  :: output_ptrs

    interface
      subroutine torch_jit_model_forward_c(model, input_tensors, n_inputs, &
                                           output_tensors, n_outputs, requires_grad) &
          bind(c, name = 'torch_jit_module_forward')
        use, intrinsic :: iso_c_binding, only : c_bool, c_ptr, c_int
        implicit none
        type(c_ptr), value, intent(in) :: model
        type(c_ptr), value, intent(in) :: input_tensors
        integer(c_int), value, intent(in) :: n_inputs
        type(c_ptr), value, intent(in) :: output_tensors
        integer(c_int), value, intent(in) :: n_outputs
        logical(c_bool), value, intent(in) :: requires_grad
      end subroutine torch_jit_model_forward_c
    end interface

    n_inputs = size(input_tensors)
    n_outputs = size(output_tensors)

    if (.not. present(requires_grad)) then
      requires_grad_value = .false.
    else
      requires_grad_value = requires_grad
    end if

    ! Assign array of pointers to the input tensors
    do i = 1, n_inputs
      input_ptrs(i) = input_tensors(i)%p
    end do

    ! Assign array of pointers to the output tensors
    do i = 1, n_outputs
      output_ptrs(i) = output_tensors(i)%p
    end do

    call torch_jit_model_forward_c(model%p, c_loc(input_ptrs), n_inputs,       &
                                   c_loc(output_ptrs), n_outputs,              &
                                   logical(requires_grad_value, c_bool))
  end subroutine torch_model_forward