Disconnected subdomains in distributed memory computations

[pmartorell]

The p4est parallel partition with z-filling curves can lead to disconnected subdomains in some configurations. Disconnected subdomains may represent an issue in the in/out propagation, e.g., if one component is inside and the other outside.

In order to deal with disconnected components one should treat each component as a single subdomain in the propagation stage.

These developments are starting at

STLCutters.jl/src/Distributed.jl

Line 44 in 4577ebc

facet_neighbors = map(compute_facet_neighbors,

We will need the following:

• compute_disconected_components(model::DistributedDiscreteModel,d=0) -> cell_to_comp,comp_to_cells (d is the dimension of connections of the parts)
• Global components: lcomp_to_gcomp
• Vectorize subdomain arrays:
  • facet_to_comp_neighbors
  • part_to_comp_to_ioc
• Vectorize gather and scatter

https://github.com/gridap/STLCutters.jl/tree/dev_disconnected_components

In the branch dev_disconnected_components there is a procedure for the generation of a model with disconnected components in the following file. This model will be useful for developing and debugging this feature in sequential without p4est