# Computing the vertex separators

Dear Professor,

for the purpose of a substructuring domain decompositioning method I want to implement, I need to have access to the separators between the various subdomains. I was thinking of using the METIS_PartMeshNodal-function to partition the mesh in N subdomains and subsequently calling METIS_NodeComputeSeparator to calculate the separators between the subdomains. Is this the most appropriate approach to this problem? It is not entirely clear to me how METIS_NodeComputeSeparator works. Does it calculate a new partition? Or will it calculate the separator between the domains PartMeshNodal has defined?

thanks,

Vincent

Submitted by vdegroof on Mon, 2014-02-10 11:25

## RE: That will not work. The

That will not work. The METIS_NodeComputeSeparator function takes a graph and computes a 3-way partitioning in which the third partition is the vertex separator. Its objective is to minimize the size of the separator while enforcing some degree of size balance for the other two partitions.

In order to find the separators between the subdomains you will need to code it yourself.