added by Nyapicom

Take sign. See also:** Documentation for [std::copysign](https://en.cppreference.com/w/cpp/numeric/math/copysign). \param x value to change sign for \

Hyperbolic cosine. This function is exact to rounding for all rounding modes. See also:** Documentation for [std::cosh](https://en.cppreference.com/w

create an empty index with the specified parameters. edge_size_for_creation : Number of edges for each node in the graph.