Dynamic load balancing parameters¶
Note
Parallel build only. Load balancing support requires the ParMETIS module to be configured and compiled.
Two factors generally cause a load imbalance between the individual subdomains:
factors coming from the nature of the application, such as a switch from linear to nonlinear response in certain regions, or local adaptive refinement;
external factors caused by resource reallocation, typical of non-dedicated cluster environments where the individual processors are shared between different applications and users, which makes the allocated processing power vary in time.
Load balance is recovered by repartitioning the problem domain and transferring the work — typically represented by finite elements — from one subdomain to another.
The corresponding part of the analysis record has the following syntax.
Syntax
[lbflag (in)] [forcelb1 (in)]
[wtp (ia)] [lbstep (in)]
[relwct (rn)] [abswct (rn)]
[minwct (rn)]
Parameters
- [
lbflag(in)] A nonzero value activates dynamic load balancing. Default
0.- [
forcelb1(in)] A nonzero value forces load rebalancing after the first solution step.
- [
wtp(ia)] Activates optional load balancing plugins. At present the only supported value is
1, which activates the nonlocal plugin, necessary for nonlocal averaging to work properly while dynamic load balancing is active.- [
lbstep(in)] Rebalancing, if needed, is performed only every
lbstep-th solution step. Default5.- [
relwct(rn)] Relative wall-clock imbalance threshold. When the relative imbalance between the wall-clock solution times of the individual processors exceeds it, the rebalancing procedure is activated. Default
0.1.- [
abswct(rn)] Absolute wall-clock imbalance threshold. When the absolute imbalance between the wall-clock solution times of the individual processors exceeds it, the rebalancing procedure is activated. Default
10.0.- [
minwct(rn)] Minimum absolute imbalance for the relative check against
relwctto be performed at all; below it, only the absolute check is done. Default0.0.