10.2 Preparing the Mesh for Adaptivity

For every element entity in the mesh, there is a desired size entry for each element. This entry is called meshSizing. This meshSizing entry contains a metric that decides the element quality. The default metric is the average of the size of the three edges of an element. This section provides various mechanisms to set this field. Some of the adaptive operations actually use these metrics to maintain quality. Though there is another metric which is computer for each element and maintained on the fly and that is the ratio of the largest length to the smallest altitude and this value during mesh adaptivity is not allowed to go beyond a certain limit. Because the larger this value after a cecrtain limit, the worse the element quality.

void FEM_ADAPT_SetElementSizeField(int meshID, int elem, double size);
For the mesh specified by meshID, for the element elem, we set the desired size for each element to be size.

void FEM_ADAPT_SetElementSizeField(int meshID, double *sizes);
For the mesh specified by meshID, for the element elem, we set the desired size for each element from the corresonponding entry in the sizes array.

void FEM_ADAPT_SetReferenceMesh(int meshID);
For each element int this mesh defined by meshID set its size to the average edge length of the corresponding element.

void FEM_ADAPT_GradateMesh(int meshID, double smoothness);
Resize mesh elements to avoid jumps in element size. i.e. avoid discontinuities in the desired sizes for elements of a mesh by smoothing them out. Algorithm based on h-shock correction, described in Mesh Gradation Control, Borouchaki et al.