Hi, I try using the compressed_sparse row_graph graph type, and I want add lots vertices. When I read the documentation (http://www.boost-consulting.com/boost/libs/graph/doc/compressed_sparse_row.h...), I saw the appropriate add_vertices function described as bellow: vertex_descriptor add_vertices(vertices_size_type count, compressed_sparse_row_graph& g) But, in compressed_sparse_row_graph.hpp:346: <--8----------------------------------------------------- template<BOOST_CSR_GRAPH_TEMPLATE_PARMS> inline Vertex add_vertices(Vertex count, BOOST_CSR_GRAPH_TYPE& g) { Vertex old_num_verts_plus_one = g.m_rowstart.size(); g.m_rowstart.resize(old_num_verts_plus_one + count, EdgeIndex(0)); return old_num_verts_plus_one - 1; } <--8----------------------------------------------------- I don't understand why `count' is a `Vertex' type! Why not `vertices_size_type' type ? Regards, -- Johan