get_partial_piecewise_val Subroutine

  pure subroutine get_partial_piecewise_val(this, upstream_grad, output)
    !! Get partial derivative of piecewise activation (in-place version)
    implicit none
    class(array_type), intent(in) :: this
    real(real32), dimension(:,:), intent(in) :: upstream_grad
    real(real32), dimension(:,:), intent(out) :: output

    where(this%left_operand%val.le.this%right_operand%val(2,1) .or. &
         this%left_operand%val.ge.-this%right_operand%val(2,1) &
    )
       output = upstream_grad
    elsewhere
       output = upstream_grad * this%right_operand%val(1,1)
    end where

  end subroutine get_partial_piecewise_val