get_partial_cos Function

  function get_partial_cos(this, upstream_grad) result(output)
    implicit none
    class(array_type), intent(inout) :: this
    type(array_type), intent(in) :: upstream_grad
    type(array_type) :: output
    logical :: left_is_temporary_local
    type(array_type), pointer :: ptr

    left_is_temporary_local = this%left_operand%is_temporary
    this%left_operand%is_temporary = .false.
    ptr => -upstream_grad * sin( this%left_operand )
    this%left_operand%is_temporary = left_is_temporary_local
    call output%assign_and_deallocate_source(ptr)
  end function get_partial_cos