The .machines file generally contains one line for each machine or processor on which a process is to be started. In each line the weight (relative speed) and the name of the machine is specified in the following form:
weight:machine_namewhere weight is an integer (e.g. a three times more powerful machine should have a three times higher weight).
During the run of lapw1para the file .processes is generated. This file is used by lapw2para to determine which case.vector* to read.
By default lapw1para will generate approximately 3 vector-files per processor, if enough k-points are available for distribution. The factor 3 is called ``granularity'' and should allow some load balancing in heterogeneous environments. If during siteconfig_lapw a shared memory system was selected, ``granularity'' will be set by default to 1.
For performance reasons a different ``granularity'' can be specified, by adding the line
granularity:new_granularityto the .machines file. On shared memory architecture machines it is sometimes advisable to add a ``residue machine'' to calculate the surplus (residual) k-points (given by the expression
residue:machine_namein the .machines file.
To distribute the remaining k-points one-by-one (and not in one junk) over all processors, the option
extrafine:1can be set in the .machines file.