multiorder laplacian

[federicomalizia]

hi,

I'm considering a "real" hypergraph, while computing the laplacians of any order I found this error:

      9 hypergraph = Hypergraph(hyperedges_list)
---> 10 laplacians = laplacian_matrices_all_orders(hypergraph)
     11 
     12 

~/anaconda3/lib/python3.9/site-packages/hypergraphx/linalg/linalg.py in laplacian_matrices_all_orders(hypergraph, weighted, shape)
    422     laplacian_matrices = {}
    423     for order in range(1, hypergraph.max_order() + 1):
--> 424         laplacian_matrices[order] = laplacian_matrix_by_order(
    425             hypergraph, order, weighted, shape
    426         )

~/anaconda3/lib/python3.9/site-packages/hypergraphx/linalg/linalg.py in laplacian_matrix_by_order(hypergraph, order, weighted, shape)
    407 
    408     #maybe wrong mapping of nodes? binary incidence returns the mapping of the nodes in the hypergraph
--> 409     degree_mtx = degree_matrix(hypergraph, order, mapping)
    410     laplacian = degree_mtx.multiply(order + 1) - incidence.dot(incidence.transpose())
    411 

~/anaconda3/lib/python3.9/site-packages/hypergraphx/linalg/linalg.py in degree_matrix(hypergraph, order, mapping)
    393         # calcolare il mapping dall'ipergrafo
    394         pass
--> 395     degree_lst = [degree_dct[inverse_mapping[n]] for n in sorted(inverse_mapping.keys())]
    396 
    397     return sparse.diags(degree_lst)

~/anaconda3/lib/python3.9/site-packages/hypergraphx/linalg/linalg.py in <listcomp>(.0)
    393         # calcolare il mapping dall'ipergrafo
    394         pass
--> 395     degree_lst = [degree_dct[inverse_mapping[n]] for n in sorted(inverse_mapping.keys())]
    396 
    397     return sparse.diags(degree_lst)

KeyError: 0

I think it is due to the presence of nodes which are not connected to any hyperedge of order 2 (triples).

[FraLotito]

Hi! Thank you for reporting this error, we are currently investigating.