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Abaqus: Difference between revisions
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=== Multiple node computing === <!--T:20832--> | === Multiple node computing === <!--T:20832--> | ||
Users with large memory or compute needs (and correspondingly large licenses) can use the following script to perform mpi-based computing over an arbitrary range of nodes ideally left to the scheduler to automatically determine. A companion template script to perform restart of multinode jobs is not provided due to additional limitations when they can be used. | |||
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#mp_host_split=1 # number of mp processes per host >= 1 (uncomment to specify) | #mp_host_split=1 # number of mp processes per host >= 1 (uncomment to specify) | ||
}} | }} | ||
=== Memory estimates === <!--T:20833--> | |||
To further tune the requested memory in the single and multiple node slurm scripts, memory estimates per compute process required to minimize I/O can be found in the output dat file of a completed job. If mp_host_split is not specified (or is set to 1) then the total number of compute processes will equal the number of nodes. The mem-per-cpu value can then be roughly determined by multiplying the largest memory estimate bye the number of nodes and then dividing by the number or ntasks. If however a value for mp_host_split is specified (greater than 1) than the mem-per-cpu value can be roughly determined from the largest memory estimate times the number of nodes times the value of mp_host_split divided by the number of tasks. Note that mp_host_split must be less than or equal to the number of cores per node assigned by slurm at runtime otherwise abaqus will terminate. This scenario can be controlled by uncommenting to specify a value for tasks-per-node. The following definitive statement is given in every output dat file and mentioned here for reference: | |||
<!--T:20885--> | |||
THE UPPER LIMIT OF MEMORY THAT CAN BE ALLOCATED BY ABAQUS WILL IN GENERAL DEPEND ON THE VALUE OF | |||
THE "MEMORY" PARAMETER AND THE AMOUNT OF PHYSICAL MEMORY AVAILABLE ON THE MACHINE. PLEASE SEE | |||
THE "ABAQUS ANALYSIS USER'S MANUAL" FOR MORE DETAILS. THE ACTUAL USAGE OF MEMORY AND OF DISK | |||
SPACE FOR SCRATCH DATA WILL DEPEND ON THIS UPPER LIMIT AS WELL AS THE MEMORY REQUIRED TO MINIMIZE | |||
I/O. IF THE MEMORY UPPER LIMIT IS GREATER THAN THE MEMORY REQUIRED TO MINIMIZE I/O, THEN THE ACTUAL | |||
MEMORY USAGE WILL BE CLOSE TO THE ESTIMATED "MEMORY TO MINIMIZE I/O" VALUE, AND THE SCRATCH DISK | |||
USAGE WILL BE CLOSE-TO-ZERO; OTHERWISE, THE ACTUAL MEMORY USED WILL BE CLOSE TO THE PREVIOUSLY | |||
MENTIONED MEMORY LIMIT, AND THE SCRATCH DISK USAGE WILL BE ROUGHLY PROPORTIONAL TO THE DIFFERENCE | |||
BETWEEN THE ESTIMATED "MEMORY TO MINIMIZE I/O" AND THE MEMORY UPPER LIMIT. HOWEVER ACCURATE | |||
ESTIMATE OF THE SCRATCH DISK SPACE IS NOT POSSIBLE. | |||
== Explicit analysis == <!--T:20833--> | == Explicit analysis == <!--T:20833--> | ||