I have some GF(2) matrices that are incidence matrices of undirected graphs. When I try to construct the graphs in sage, this happens:
sage: Graph(matrix(GF(2), [[1,0,1,1],[1,1,0,1],[0,1,1,0]])) --------------------------------------------------------------------------- ValueError Traceback (most recent call last) <ipython-input-1-cf6c24cef566> in <module>() ----> 1 Graph(matrix(GF(Integer(2)), [[Integer(1),Integer(0),Integer(1),Integer(1)],[Integer(1),Integer(1),Integer(0),Integer(1)],[Integer(0),Integer(1),Integer(1),Integer(0)]])) /Applications/sage/local/lib/python2.7/site-packages/sage/graphs/graph.pyc in __init__(self, data, pos, loops, format, boundary, weighted, implementation, sparse, vertex_labels, name, multiedges, convert_empty_dict_labels_to_None) 1288 multiedges = ( len(uniq(positions)) < total ) 1289 except AssertionError: -> 1290 raise ValueError(msg) 1291 num_verts = data.nrows() 1292 elif format == 'Graph': ValueError: Non-symmetric or non-square matrix assumed to be an incidence matrix: Each column represents an edge: -1 goes to 1. sage: Is there a way around this, apart from manually changing each column so that it has a -1 in it? Michael -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
