static arg: bin or particle
    bin = balance by bin count
    particle = balance by particle count
  dynamic args: N threshhold
    N = test whether to balance every N steps
    threshhold = only balance if imbalance is greater than threshhold 

file = filename for storing sub-domain boundaries (optional)

Examples:

bin static particle
bin dynamic 1000 1.5 out.file 

Description:

For parallel runs of spatial simulations, determine how bins are partitioned across processors.

If this command is not used, the set of 3d bins are partitioned into small 3d bricks, one per processor.

If "static bin" is used, bins are partitioned by recursive coordinate bisectioning (RCB) one time at the beginning of the 1st run. Each bin is weighted the same, no matter how many particles it contains.

If "static particle" is used, bins are partitioned by recursive coordinate bisectioning (RCB) at the beginning of each run. Each bin is weighted by the number of particles it contains.

If "dynamic" is used, bins are re-partitioned every N timesteps, with each bin weighting by their current number of particles. Re-partitioning only occurs if the imbalance factor exceeds the specfied threshhold. The imbalance factor is the ratio of the maximum particles on any processor divided by the average particles across all processors, so an imbalance factor or 1.0 is perfect balance.

File is an optional argument. If specified the load balance partitions are written to the file each time the balancer is invoked, formatted as a surface of triangles which can be visualized with the Pizza.py toolkit.

Restrictions:

This command can only be used for spatial simulations.

Related commands: none

Default:

Static partitioning of bins as 3d bricks.