get_partial_softmax_reverse_right_val Subroutine

  pure subroutine get_partial_softmax_reverse_right_val(this, upstream_grad, output)
    !! Get partial derivative of softmax reverse operation (in-place version)
    implicit none
    class(array_type), intent(in) :: this
    real(real32), dimension(:,:), intent(in) :: upstream_grad
    real(real32), dimension(:,:), intent(out) :: output

    integer :: dim, i
    real(real32), dimension(size(this%val,3-this%indices(1))) :: sum_yu

    dim = this%indices(1)
    if(dim.eq.1)then
       sum_yu = sum(this%left_operand%val * upstream_grad, dim=dim)
       do concurrent(i=1:size(this%val,1))
          output(i, :) = upstream_grad(i, :) - sum_yu(i) * this%left_operand%val(i, :)
       end do
    else
       sum_yu = sum(this%left_operand%val * upstream_grad, dim=dim)
       do concurrent(i=1:size(this%val,2))
          output(:, i) = upstream_grad(:, i) - sum_yu(i) * this%left_operand%val(:, i)
       end do
    end if
  end subroutine get_partial_softmax_reverse_right_val