LohCG computational performance

Strong scaling of computation

Using increasing number of compute cores with the same problem measures strong scaling, characteristic of the algorithm and its parallel implementation. Strong scalability helps answer questions, such as How much faster one can obtain a given result (at a given level of numerical error) if larger computational resources were available. To measure strong scaling we ran the Lid-driven cavity using a 794M-cell mesh (133M points) on varying number of CPUs for a few time steps and measured the average wall-clock time it takes to advance a single time step. The figure below depicts timings measured on the LUMI computer.

The figure shows that the LohCG solver scales ideally up to 65K CPU cores.

Comparing the same data on ChoCG shows that the LohCG solver is approximately 100-200x faster for the same problem size using the same resources.