Ncon values when vertices refers to nodes and only edges are weighted

Hello,

I am trying to partition a triangular finite element mesh using ParMETIS_V3_PartKway. I am converting from ParMETIS 2.0 and the ParMETIS_PartKway function.

In the code using 2.0, vtxdist corresponds to the number of nodes on each processor, wgtflag is set to 1 and an edge weighting is built into the array adjwgt.

I am confused as to what the value of ncon should be, and thus the sizes of tpwgts and ubvec. I initially thought that ncon should be zero, since there are weights only on the edges and not the vertices, since vtxdist is referring to the nodes.

This doesn't work, so should ncon be 3. This would mean the "vertices" are elements and each element has 3 weights corresponding to the 3 edges?

Also can ncon =0 if wgtflag = 0 and thus tpwgts = ubvec = adjwgt = vwgt = NULL ?

Thank you.