Welcome to the LS-DYNA support site At this site you will find answers to basic and advanced questions that might occur while using LS-DYNA. Furthermore it will provide information about new releases and ongoing developments. The content will be regularly updated with answers to frequent questions related to LS-DYNA. Ansys LS-DYNA is the industry-leading explicit simulation software used for applications like drop tests, impact and penetration, smashes and crashes, occupant safety, and more. LSTC is committed to reducing customer costs by ensuring that LS-DYNA is the fastest and most scalable software available and by providing FEA models and peripheral software LS-DYNA ATD and barrier models LS-DYNA pre/post processing software.
Both 32-bit and 64-bit executables in both serial and parallel versions are provided. The MPIparallel versions use OpenMPI as their MPI parallel library, the HPC Center's default version ofMPI. The serial executable can also be run in OpenMP (not to be confused with OpenMPI) node-local SMP-parallel mode. The names of the executable files in the '/share/apps/lsdyna/default/bin'directory are:
Those with the string 'mpp' in the name are the MPI distributed parallel versions of the code. Theinteger (32 or 64) designates the precision of the build. In the examples below, depending on thetype of script being submitted (serial or parallel, 32- or 64-bit), a different executable will be chosen. The scaling properties of LS-DYNA in parallel mode are limited, and users should notcarelessly submit parallel jobs requesting large numbers of cores without understanding howtheir job will scale. A large 128 core job that runs only 5% faster than a 64 core job is a wasteof resources. Please examine the scaling properties of your particular job before scaling up.
As is the case with most long running applications run at the CUNY HPC Center, whether parallelor serial, LS-DYNA jobs are run using a PBS batch job submission script. Here we provide someexample scripts for both serial and parallel execution.
Note that before using this script you will need to setup the environment for LS-DYNA. On Andy 'modules' is used to manage environments. Setting up LS-DYNA is done with
First an example serial execution script(called say 'airbag.job') run at 64-bits using the LS-DYNA 'airbag' example ('airbag.deplo.k') fromthe examples directory above as the input.
Details on the SLURM options at the head of the this script file are discussion below,but in summary '-q production_qdr' selects the routing queue into which the job willbe placed, '-N ls-dyna_serial' sets this job's name, 'nodes=1 ntasks=1 mem=2880'nodes-requests 1 SLURM resource chunk that includes 1 cpu and 2880 MBytes of memory, allows SLURM to put the resources needed for the job any where on theANDY system.
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The LS-DYNA command line sets the input file to be used and the amount of in-corememory that is available to the job. Note that this executable does NOT include thestring 'mpp' which means that it is not the MPI executable. Users can copy the 'airbag.deploy.k'file from the examples directory and cut-and-paste this script to run this job. It takes a relatively sort time to run. The SLURM command for submitting the job would be:
Here is a SLURM script that runs a 16 processor (core) MPI job. This script isset to run the TopCrunch '3cars' benchmark which is relatively long-running usingMPI on 16 processors. There are a few important differences in this script.
Focusing on the difference in this script relative to the serial SLURM script above. First, the '-l select' linerequests not 1 SLURM resource chunk, but 16 each with 1 cpu (core) and 2880 MBytes of memory. Thisprovides the necessary resources to run our 16 processor MPI-parallel job. Next, the LS-DYNA commandline is different. The LS-DYNA MPI-parallel executable is used (ls-dyna_mpp64.exe), and it is run with the help of the OpenMPI job submission command 'mpirun' which sets the number of processorsand the location of those processors on the system. The actually LS-DYNA key words also add thestring 'ncpu=16' to instruct LS-DYNA that this is to be a parallel run.
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Running in parallel on 16 cores in 64-bit mode on ANDY, the '3cars' case takes about 9181 secondsof elapsed time to complete. If the user would like to run this job, they can grab the input files outof the directory '/share/apps/lsdyna/default/examples/3cars' on ANDY and use the above script.
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