Appendix D. XXUSB SpecTcl with MPI parallelism

Only VMUSBSpecTcl has been made to support MPI parallel operation. If CCUSBSpecTcl is run under mpirun it will output an error message and exit immediately with an error status.

VMUSB SpecTcls require that configuration support packages and configuration scripts be loaded into all of the processes of MPI SpecTcl. This ensures that all parameters, spectra and decode tables get loaded whereever they are needed.

If you are taking the skeletons for these versions of SpecTcl from 7.0 or later everything should just work. If, on the other hand you are moving to SpecTcl 7.0 from an earlier version, this appendix describes what you need to do to make the transition:

1. Ensure the MPI Tcl package is loaded in all ranks.

2. Edit SpecTclRC.tcl so that the configuration part of that script is executed in all ranks.

Loading the MPI Tcl package in all ranks is accomplised by adding the following lines to your SpecTclInit.tcl

load [file join $SpecTclHome lib/libMPITclPackage.so]
package require mpi
        

Be sure to put these lines in SpecTclInit.tcl not in SpecTclRC.tcl.

This has been added to the SpecTclInit.tcl that is now in the VMUSBSkel directory of the SpecTcl insallation.

 mpi::send all {
	set daqconfig [file join daqconfig.tcl]; # default config file.
	lappend auto_path [file join $SpecTclHome TclLibs]
	package require vmusbsetup

	vmusbConfig $daqconfig
}