LS-DYNA Automatic Re-Decomposition

The default decomposition method for LS-DYNA/MPP is RCB which dividing the model based on the initial geometry. If the geometry does not severely distorted during the simulation, this decomposition gives reasonable scaling upto few hundreds cores. LS-DYNA also provides additional “pfile” options which relies on user’s knowledge of deformation to achieve better MPP efficiency. Unfortunately, there are many problems cannot be easily treated by those options, i.e. bird strike, water wading, FBO, etc. The simulations involve parts with relative motion which are difficult to decompose only once and those jobs are usually suffer from the scaling. Furthermore more cores are used in the simulation, a load unbalancing effects will be amplified and results in poor scalability. To Achieve better computational load balancing, a new automatic re-decomposition algorithm has been implemented recently. The new method can readjust the load balancing during simulation based on the current geometry. In this study, we will give some typical examples to show how to regain the load balancing and improve the parallel efficiency.