Products: Abaqus/Standard Abaqus/Explicit Abaqus/CFD
Co-simulation between Abaqus/Standard, Abaqus/Explicit, and Abaqus/CFD, the Abaqus analysis modules, can be executed by running the Abaqus co-simulation procedure. Several parameters can be set either on the command line or in the environment file (see “Using the Abaqus environment settings,” Section 3.3.1).
A co-simulation analysis executes two “child” analyses and directs the communication of the two processes. The co-simulation execution procedure allows you to enter a single command to run the co-simulation and is the recommended procedure for Abaqus/CFD to Abaqus/Standard or to Abaqus/Explicit co-simulation; it is an alternative to running the co-simulation using the Abaqus execution procedure, which requires that you enter two separate commands. Refer to “Abaqus/Standard, Abaqus/Explicit, and Abaqus/CFD execution,” Section 3.2.2, for instructions on submitting co-simulation analyses separately.
The co-simulation execution procedure supports a subset of the options that are available for the Abaqus execution procedure; these options are included in the command summary below.
Three methods are available for allocating CPUs to child analysis jobs for parallel processing: specifying the number of CPUs for each job, distributing CPUs between analysis jobs, and distributing CPUs between analysis products.
The most direct method of allocating CPUs is to specify the number of CPUs to be used for each child analysis. You provide a comma-separated pair of values using the cpus parameter.
You can specify the total number of CPUs to be used for your co-simulation analysis and weighting factors that determine the distribution of the CPUs between the two child analyses. This method enables you to specify a CPU count that relates directly to your resource limits and to describe the relative computational needs of the two child analyses. You provide one value for the number of CPUs to allocate for the co-simulation using the cpus parameter, and you define weight factors using the cpuratio parameter.
Weight factors are floating point numbers and are considered in a normalized sense. For example, if you wish to specify that the CPU allocation for the first child job is four times that of the second job, you can provide any of the following pairings:
cpuratio=4.0,1.0 cpuratio=16,4 cpuratio=0.8,0.2
You can specify the total number of CPUs to be used for your co-simulation analysis and weighting factors that determine the distribution of the CPUs between the analysis products involved in the co-simulation. This method enables you to specify a CPU count that relates directly to your resource limits and to describe the relative computational needs of the two child analyses based on the analysis product used (Abaqus/Standard, Abaqus/Explicit, or Abaqus/CFD). You provide one value for the number of CPUs to allocate for the co-simulation using the cpus parameter, and you define weight factors in the environment file using the cpus_weight_std, cpus_weight_xpl, and cpus_weight_cfd environment variable parameters (see “Co-simulation parameters” in “Using the Abaqus environment settings,” Section 3.3.1).
Weight factors are interpreted in a normalized sense. For example, if you wish to specify that the CPU allocation for the Abaqus/CFD analysis is twice that of the Abaqus/Explicit analysis, you define the parameters in the environment file as follows:
cpus_weight_xpl=1 cpus_weight_cfd=2
In cases where the distribution of the CPUs between analysis jobs or analysis products does not result in whole numbers, Abaqus rounds down the CPU allocation for the first job listed in the job parameter and rounds up the allocation for the second job listed. For example, if 8 CPUs are allocated and the CPU allocation for the Abaqus/CFD analysis is twice that of the Abaqus/Explicit analysis, the distribution between Abaqus/Explicit and Abaqus/CFD is 2/6 if the Abaqus/Explicit job is listed first and is 3/5 if the Abaqus/CFD job is listed first.
Command line options that pertain to the child analyses require you to enter a comma-separated pair of values. The order of entries in the pairing must be consistent for all child analysis options to obtain the desired co-simulation execution behavior. For example, in an Abaqus/Standard to Abaqus/Explicit co-simulation, if you specify the job name for the Abaqus/Standard analysis as the first entry for the job parameter, the first entry for the remainder of the child analysis options will apply to the Abaqus/Standard analysis.
If an option is relevant for only one of the child analyses, you can enter a value of NONE for the analysis in which the option is not relevant. In cases where you wish to use the default settings for an option for both child analyses or wish to use environment settings to control the behavior, you need not provide that option in the command line.
The following limitations apply to the co-simulation execution procedure:
Only co-simulation between two analyses is supported.
The analyses can be run only on a single machine or a compute cluster where the head node can be shared by both child analysis jobs.
Co-simulation with third-party applications is not supported with this execution procedure; for information on Abaqus job execution for co-simulation with third-party applications, consult the third-party program documentation.
abaqus cosimulation | cosimjob=cosim-job-name |
job=comma-separated pair of job names [cpus={number-of-cpus | comma-separated pair of number-of-cpus}] [cpuratio=comma-separated pair of weight factors specifying cpu allocation to child analyses] [interactive | background | queue=[queue-name][after=time]][timeout=co-simulation timeout value in seconds] [portpool=colon-separated pair of socket port numbers] [input=comma-separated pair of input-file names] [user=comma-separated pair of {source-file | object-file} names] [globalmodel=comma-separated pair of {results file | output database file} names] [memory=comma-separated pair of memory-sizes] [oldjob=comma-separated pair of oldjob-names] [double=comma-separated pair of double precision executable settings] [scratch=comma-separated pair of scratch-dir names] [output_precision=comma-separated pair of {single | full} ] |
This option specifies the name of the co-simulation summary log file generated during the run. If this option is omitted from the command line, you will be prompted for its value.
The comma-separated values of this option specify the names of all child analysis files generated during the run. If this option is omitted from the command line, you will be prompted for its value.
This option is used to specify how CPUs are allocated for the co-simulation during parallel processing. The default value for this parameter is 2 and can be changed to a value greater than 2 in the environment file (see “Using the Abaqus environment settings,” Section 3.3.1).
If this option is set equal to a single value, that value specifies the total number of processors allocated for the co-simulation, which can be distributed between child analyses or between analysis products. The distribution of the CPUs between child analyses is split evenly by default and may be further controlled either by using the cpuratio parameter or by defining the distribution of the CPUs between analysis products by setting the cpus_weight_std, cpus_weight_xpl, and cpus_weight_cfd environment file parameters (see “Co-simulation parameters” in “Using the Abaqus environment settings,” Section 3.3.1).
If this option is set equal to a comma-separated pair of values, these values specify the number of processors to be used for each child analysis.
The comma-separated values of this option specify the relative weighting of the distribution of processors allocated to each child analysis. This option is valid only when the cpus option is set to a single value.
This option causes the co-simulation job to run interactively. A summary log file will be output to the screen, and the child analysis summary output will be written to their separate log files.
This option submits the co-simulation job to run in the background, which is the default. Log file output is saved for the co-simulation job in the file cosim-job-name.log and in the child analysis files job-name.log in the current directory.
This option submits the co-simulation job to a batch queue. If the option appears with no value, the job is submitted to the system default queue. Quoted strings are allowed. The available queues are site specific. Contact your site administrator to find out more about local queuing capabilities.
This option is used in conjunction with the queue option to specify the time at which the job will start in the selected batch queue. This capability is supported for each individual site through the Abaqus environment file. (See the Abaqus Installation and Licensing Guide for details.)
This option is used to specify a timeout value in seconds for the co-simulation connection. Abaqus terminates if it does not receive any communication between the child analysis processes during the time specified. The default value is 3600 seconds. The default timeout value that Abaqus uses can be set with the cosimulation_timeout parameter in the environment file (see “Using the Abaqus environment settings,” Section 3.3.1).
This option is used to specify a colon-separated pair of TCP/UDP port numbers that represent the start and end value of port numbers to be used when establishing connections between the child processes. The default range is 51000:52000. The default range that Abaqus uses can be set with the portpool parameter in the environment file (see “Using the Abaqus environment settings,” Section 3.3.1).
The comma-separated values of this option specify the child analysis input file names, which may be given with or without the .inp extension (if the extension is not supplied, Abaqus appends it automatically). For each child analysis, if this option is not supplied, the procedure looks for an input file called job-name.inp in the current directory. If job-name.inp cannot be found, the procedure prompts for the input file name.
The comma-separated values of this option specify the names of FORTRAN source or object files that contain any user subroutines to be used in the analysis. The names of the user routines may contain a path name and may be given with or without a file extension. This option is not applicable for Abaqus/CFD.
The comma-separated values of this option specify the names of the global model's results (.fil) file or output database (.odb) file from which the results are to be interpolated to drive a submodel analysis. This option is required whenever a submodel analysis or submodel boundary condition reads data from the global model's results. The file extension is optional. If both a results file and an output database file exist for the global model and no extension is given, the results file is used. This option is not applicable for Abaqus/CFD.
The comma-separated values of this option specify the maximum amount of memory or maximum percentage of the physical memory that can be allocated during the input file preprocessing and during the Abaqus/Standard analysis phase (see “Managing memory and disk use in Abaqus,” Section 3.4.1). This option is not applicable for Abaqus/CFD.
The comma-separated values of this option specify the names of the files from a previous run from which a restart run is to be started or from which results are to be imported. A path or file extension is not allowed. This option is required when a restart or import analysis reads data from the restart file. The oldjob-names must be different from the current job-names.
This option is applicable only for an Abaqus/Explicit analysis.
The comma-separated values of this option specify the double precision executable settings to be used; the value for the Abaqus/Standard or Abaqus/CFD analysis is always NONE. The possible values for the Abaqus/Explicit analysis are both, constraint, explicit, and off. This capability is also supported through the Abaqus environment file with the environment variable double_precision (see “Using the Abaqus environment settings,” Section 3.3.1).
If double=both, both the Abaqus/Explicit packager and analysis will run in double precision.
If double=constraint, the constraint packaging and constraint solver in Abaqus/Explicit will run in double precision, while the Abaqus/Explicit packager and Abaqus/Explicit analysis continue to run in single precision.
If double=explicit, the Abaqus/Explicit analysis will run in double precision, while the packager will still run in single precision. The default value is explicit.
If double=off, the environment file setting is overridden if necessary to invoke both the Abaqus/Explicit packager and Abaqus/Explicit analysis in single precision. For a discussion of when to use the double precision executable, see “Procedures: overview,” Section 6.1.1.
The comma-separated values of this option specify the names of the directories used for scratch files. On UNIX platforms the default value is the value of the $TMPDIR environment variable or /tmp if $TMPDIR is not defined. On Windows platforms the default value is the value of the %TEMP% environment variable or \TEMP if this variable is not defined. During the analysis a subdirectory will be created under this directory to hold the analysis scratch files.
The comma-separated values of this option specify the precision of the nodal field output written to the output database files (job-name.odb). Using output_precision=full results in double precision field output for Abaqus/Standard analyses. To obtain double precision field output for Abaqus/Explicit analyses, use the double option in addition to using output_precision=full. Nodal history output is available only in single precision. This option is not applicable for Abaqus/CFD.
The following examples illustrate the different functions and capabilities of the abaqus cosimulation execution procedure.
Use the following command to run a co-simulation between a heat transfer analysis called “solid_heat” and a fluids analysis called “fluid”, interactively:
abaqus cosimulation cosimjob=cosim_cht job=solid_heat,fluid interactive
Use the following command to run a co-simulation between an Abaqus/Explicit analysis called “beam” and an Abaqus/CFD analysis called “fluid” and to allocate 8 cores to the Abaqus/Explicit job and 16 cores to the Abaqus/CFD job:
abaqus cosimulation cosimjob=beam_fluid job=beam,fluid cpus=8,16Equivalent results would be obtained using the following command:
abaqus cosimulation cosimjob=beam_fluid job=beam,fluid cpus=24 cpuratio=1,2Alternatively, you can specify settings for co-simulation environment variable parameters in the environment file and run the co-simulation execution procedure. Use the following combination of environment file settings:
ask_delete=OFF # The following parameters set the CPU # allocation by analysis product cpus_weight_xpl=1 cpus_weight_std=1 cpus_weight_cfd=2Use the following command:
abaqus cosimulation cosimjob=beam_fluid job=beam,fluid cpus=24
Use the following command to submit a co-simulation for an Abaqus/Explicit analysis called “beam” and an Abaqus/Standard analysis called “beam2” to a batch queue named “long” and to allocate 8 cores to the Abaqus/Explicit analysis and 4 cores to the Abaqus/Standard analysis:
abaqus cosimulation cosimjob=beam job=beam,beam2 cpus=8,4 queue=long