Red Black Parallel Gauss Seidel III
Do normal block decomposition
Parallel Phase I: Update all Red Points
- Communicate black points at k-1 to halo in each processor
- Compute red points to iterate k
Parallel Phase II: Update all Black Points
- Communicate red points at k to halo in each processor
- Compute black points to iterate k
This has similar efficiency analysis to Jacobi except a little more sensitive to latency
- Same amount of communication but twice as many messages
In electrical power system and similar simulations, one gets irregular sparse matrices and no way to get such a clean parallel algorithm
- In fact not clear if there is a sequential Gauss Seidel that converges