After successfully compiling the various CMAQ programs, use the distributed run scripts to generate the CCTM input files and then to run the CCTM for the CMAQ benchmark case. The CCTM must be run last in the simulation sequence; there are no other dependencies between the other CMAQ programs (except that MCIP must provide necessary information to ICON and BCON), so they can be run in any order to create input data for the CCTM. If all of the programs compiled and the CMAQ environment variables are set correctly, then for all programs other than the CCTM the benchmark simulation will execute without any modifications to the run scripts. The CCTM is configured to run in multiprocessor (parallel) mode and requires setting the number of processors to allocate to the simulation and the location of the MPI initialization command on your system.
Configuring the CCTM run script for parallel processing requires selecting the number of processors to use for the simulation by setting the NPROCS environment variable, and choosing the domain decomposition configuration by setting the variable NPCOL_NPROW. The number of processors must be equal to the product of the two values selected for NPCOL_NPROW. For example, if your system has six processors available to run CMAQ, set NPROCS to 6 and NPCOL_NPROW equal to “3 2”. For single-processor computing set NPROCS to 1 and NPCOL_NPROW to “1 1”. Most clustered multiprocessor systems require a command to start the MPI run-time environment. The CCTM run script is configured by default to use the mpirun command. Consult your system administrator to find out how to invoke MPI when running multiprocessor applications.