MacroModel Reference Manual - ISP

Chapter 4: Operation Codesarg1Number of hosts to check for availabilityarg1 specifies how many hosts in the schrodinger.hosts file (see Section 2.2 onpage 17), will be checked for availability for a specific distributed run. If any hostsare not available, they are removed from the list of hosts to be used for the specifiedjob. Each host that is checked but unavailable decreases the number of hosts overwhich the job will be distributed. Only hosts read and available will be used.For example, if the schrodinger.hosts file lists ten hosts, and arg1 is set to 5,then the first five hosts listed in the scmchrodinger.hosts file will be checked foravailability. If two of the first five hosts are unavailable, the job will be distributedover three hosts.arg2 Job sizeFor non-serial searches arg2 specifies the number of steps from the search thatshould be carried out by each job. The total number of steps is the number given byarg1 of the search command (i.e. arg1 of MCMM, LMCS, orLMC2) and the total numberof jobs is roughly given by arg1 of the search command divided by arg2 ofNPRC.For serial calculations, such as minimizations of multiple input structures and serialsearches this argument specifies the number of input structures given to each job forminimization or searching. In serial searches separate searches are conducted foreach structure in the input structure file. Serial searches can be conducted for MCMM,LMCS, LMC2, mixed LMCS/MCMM and SPMC searches. The total number of jobs isgiven by the number of structures in the input structure file divided by arg2 of NPRC.If the total number of jobs is significantly larger than some small multiple of thenumber of hosts specified by arg1 of NPRC, load balancing can take place by sendingmore jobs to the machines that finished their assigned jobs faster. The number ofjobs should not be too large, as this would result in overhead associated with startingmany jobs and organizing the results from many jobs.0 For non-serial searches, set the number of steps per job to the total number of stepsfor the search divided by the number of processors (arg1).For serial searches, set the number of structures to process per job to the number ofstructures in the input structure file divided by the number of processors.In either case, this setting is sub-optimal since no load balancing can be carried out.MacroModel 9.7 Reference Manual 153