coolfluid/coolfluid3 — Issue #196: Global indices should support peta-scale parallelization
Author: wdeconinck
Created: 2012-03-01 12:20:13+00:00
State: open
Labels: API

Not that we will get there anytime soon, but our data-structure should allow vertex and element GLOBAL indices that have higher values than the 32 bit limitation of unsigned int. (around 4-billion).

Second reason: node-matching algorithms use higher-precision than 32-bit. If we could use global indices of 64 bits, then renumbering algorithms may not be necessary for load-balancing and mesh-partitioning.

Concrete:
- List\ should be used for storing global indices.
- PE::CommPattern should be aware that these global-indices can be enormous.

I foresee mainly an issue with the PE::CommPattern.
An alternative way has to be found to map the global to local indices. Obviously we cannot store a std::vector\ with size larger than a billion, to map it to a local index.
Anyhow, what we currently have is not a good solution for the current case either, where the 32-bit limit is also already too high to store a vector of this magnitude on every rank.

Could I assign @tbanyai for the CommPattern, and once that is done, I myself will take the mesh part on me.