On Thu, Nov 14, 2013 at 11:22 AM, Frederik Elwert <[email protected]> wrote: [...] > Maybe igraph should check before it tries the projection, and give a > more informative message if the graph is not bipartite?
Indeed, the error message should be better, I'll improve it. Thanks, Best, Gabor > Regards > Frederik > > > > Am Do 14 Nov 2013 04:27:09 CET schrieb [email protected]: >> Great! >> >> Should I email it to you? >> >> >> Il 14.11.2013 03:10 Gábor Csárdi ha scritto: >>> Internal igraph vertex ids start from 0 in C, and from 1 in R, and >>> they are never negative. The not very helpful error message is coming >>> from the igraph C library and is a consequence of some other error, >>> probably in the R package, or maybe a bug in igraph. >>> >>> Your data is not very big, actually, so if you save it with save() and >>> send it to me with the complete code that you used, I can probably >>> help you. Assuming you are allowed to share the data. >>> >>> Gabor >>> >>> On Wed, Nov 13, 2013 at 9:59 PM, <[email protected]> wrote: >>>> I have a problem with the function bipartite.projection() which returns >>>> >>>> Error in bipartite.projection(igraph_bi) : >>>> At structure_generators.c:84 : Invalid (negative) vertex id, Invalid >>>> vertex id >>>> >>>> when trying to project my bipartite graph. >>>> >>>> Unfortunately my graph is very large (IGRAPH DN-B 154626 448387 -- ) >>>> so I >>>> can't easily reproduce the error in a minimum working example to share. >>>> >>>> What I tried to do was to have a look at the dataframes that I used to >>>> create the graph object in the first place with >>>> >>>> graph.data.frame(edges, directed=TRUE, vertices=nodes) >>>> >>>> I checked the "id" column of my "nodes" df along with the "from" >>>> column of >>>> my "edges" df for negative values. (By the way, both "id" and "from" >>>> columns >>>> are character vectors, not numeric). Indeed I found 25 "negative" >>>> strings in >>>> my "id" column of the "nodes" df--it depends on the first character, >>>> non-alphanumerics make for a negative value of the string. But still >>>> after >>>> removing all the negative strings, and after double-checking again >>>> both "id" >>>> and "from" columns, I keep getting the same error from >>>> bipartite.projection() >>>> >>>> Error in bipartite.projection(igraph_bi) : >>>> At structure_generators.c:84 : Invalid (negative) vertex id, Invalid >>>> vertex id >>>> >>>> Now my problem is to understand how to find where the negative >>>> values that >>>> trigger the error are hidden. >>>> >>>> Is the value of the column "id" used as id of the node without any >>>> transformation (and same for the column "from" for edges) by the >>>> function >>>> graph.data.frame? >>>> >>>> How can I get the id values out of the graph object to check for >>>> negative >>>> values? >>>> >>>> _______________________________________________ >>>> igraph-help mailing list >>>> [email protected] >>>> https://lists.nongnu.org/mailman/listinfo/igraph-help >>> >>> _______________________________________________ >>> igraph-help mailing list >>> [email protected] >>> https://lists.nongnu.org/mailman/listinfo/igraph-help >> >> _______________________________________________ >> igraph-help mailing list >> [email protected] >> https://lists.nongnu.org/mailman/listinfo/igraph-help > > _______________________________________________ > igraph-help mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/igraph-help _______________________________________________ igraph-help mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/igraph-help
