diff --git a/gtsam/nonlinear/NonlinearFactor.h b/gtsam/nonlinear/NonlinearFactor.h index b87d1bfaa..249891397 100644 --- a/gtsam/nonlinear/NonlinearFactor.h +++ b/gtsam/nonlinear/NonlinearFactor.h @@ -28,7 +28,41 @@ #include #include + +#if BOOST_VERSION >= 106600 #include +#else +namespace boost { +namespace mp11 { +// Adapted from https://stackoverflow.com/a/32223343/9151520 +template +struct index_sequence { + using type = index_sequence; + using value_type = size_t; + static constexpr std::size_t size() noexcept { return sizeof...(Ints); } +}; +namespace detail { +template +struct _merge_and_renumber; + +template +struct _merge_and_renumber, index_sequence > + : index_sequence {}; +} // namespace detail +template +struct make_index_sequence + : detail::_merge_and_renumber< + typename make_index_sequence::type, + typename make_index_sequence::type> {}; +template <> +struct make_index_sequence<0> : index_sequence<> {}; +template <> +struct make_index_sequence<1> : index_sequence<0> {}; +template +using index_sequence_for = make_index_sequence; +} // namespace mp11 +} // namespace boost +#endif namespace gtsam {