# Any tips/tricks to improve quality on structured meshes?

Hi,

I'm working with a rectangular 3-d grid one might use to perform a finite-difference calculation modeling heat conduction through a long square-cross-section rod. A nice structured grid comprised of about 100,000 hexes. I have the cells as my "vertices" and the faces between cells as my adjacency array. Both vertices and edges are weighted, adjwgt = vwgt = 1 for all edges and vertices.

I'm using the METIS 4.0.1 lib with k-way partitioning with the default options and it's not producing the right answer, i.e. nice perfectly vertical "cross-section" cuts, evenly spaced along the length of the duct. That's an obvious solution, visually, that minimizes the number of edges cut and can have a perfect load balance if the cuts are chosen at even intervals. While I get mostly cross-sectional cuts, they are very rough - lots of "shelves".

Is this to be expected? Did the refinement process get stuck or decide the result was good enough? Are there tricks in handling this kind of mesh?

Thanks for any advice more experienced users may have to offer....

Ed

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## RE: Unfortunately there are no

Unfortunately there are no tricks. This is a known problem with Metis as its routines are optimized for unstructured graphs and for structured graphs produce solutions that may not be very visually pleasing. However, the cuts should not be very far away from the optimal. Are they?