optimad / bitpit

Open source library for scientific HPC
http://optimad.github.io/bitpit/
GNU Lesser General Public License v3.0
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patchkernel: rework evaluation of characteristic size of three-dimensional elements #383

Closed andrea-iob closed 1 year ago

andrea-iob commented 1 year ago

The updated formulas are more appropriate when the characteristic size is used for the evaluation of the timestamp in transient simulations. Also, the evaluation of the characteristic size for polygons and polyhedra was missing.

When no better formula is known, characteristic size is evaluated as the volume divided by the area of the largest face (or by the area divided by the length of the longest face for two-dimensional elements).

andrea-iob commented 1 year ago

In some contexts, the updated equations can still provide a size than is larger/smaller that desired. We may want to implement other functions for those specific cases (for example, the levelset provides formulas for evaluating the radius of the tangent sphere or the radius of the bounding sphere).