// Homology computation in Gmsh finds representative chains of (relative) homology spaces using a mesh of a model. Those representatives generate the (relative) homology spaces of the model. Alternatively, Gmsh can only look for the ranks of the (relative) homology spaces, the Betti numbers of the model.
// The generators chains are stored in a given .msh-file as physical groups, whose mesh elements are oriented such that their coefficients are 1 in the generator chain.