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Note: |
Your system administrator may need to modify the script to make it compatible with your system. |
To run OptiStruct on UNIX from the command line, type the following:
<install_dir>/altair/scripts/optistruct "filename" –option argument
To run OptiStruct from a Windows DOS prompt, type the following:
<install_dir>\optistruct\bin\win32\optistruct.bat "filename" –option argument
The options and arguments are described under Options for Running OptiStruct.
OptiStruct looks for "filename" in the following manner ("filename" may contain a file path that is either absolute or relative to the run directory):
· First, it checks to see if "filename" exists exactly as input.
· If "filename" does not exist exactly as input, and if "filename" does not contain an extension (i.e. if the actual file name without the path does not contain a period), then it checks for "filename".parm and then for "filename".fem.
If none of these checks results in a match, OptiStruct reports an error and terminates.
Environment Variables
The following environment variables are optional and may be set on either UNIX or PC platforms; however, the preferred way is to define them using the OptiStruct Configuration File.
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OS_RAM = xxx |
xxx – Memory limit in Mb (Default = 1GB for 64-bit solver version and 320MB for 32-bit solver version – can be overwritten by the definition in the script). OptiStruct will attempt to run at least the minimum core solution regardless of the memory limit. |
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OS_RAM_INIT = yy |
yy – Initial memory in Mb (Default = 10% of OS_RAM). |
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OS_TMP_DIR = path |
Path – Path name to directory for scratch file storage (Default = directory where OptiStruct is started – can be overwritten by the definition in the script or input deck). |
The following environment variable is optional and may only be set on UNIX platforms; however, the preferred way is to define this using the OptiStruct Configuration File.
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DOS_DRIVE_$ = path |
This environment variable allows drive letters to be assigned to UNIX paths. This facilitates copying files which contain INCLUDE, TMPDIR, INFILE or OUTFILE definitions containing drive letters from PC to UNIX on hybrid networks. $ - Drive letter to be defined (case sensitive). Path - UNIX path with which you want to replace the drive letter. Note that after such expansion, the paths are always interpreted as if there were a ‘\’ immediately after the drive letter in the original PC path. |
The OptiStruct Configuration File
An OptiStruct configuration file may be used to establish default settings for OptiStruct either system wide, for a particular user, or for a local directory. A full description of the settings allowed and the usage of the configuration file is provided on the OptiStruct Configuration File page.
Memory Allocation in OptiStruct
OptiStruct dynamically allocates the memory for a run. The allocation starts with the initial memory.
The default setting for the memory limit is 1GB for 64-bit solver version and 320MB for 32-bit solver version (PC and Linux). This setting can be changed by using the environment variable OS_RAM, or by defining the –len option in the run script. The script overwrites the environment variable.
OptiStruct will always attempt to assign enough memory for a minimum core solution.
The initial memory is 10% of the memory limit by default. This setting can be changed by using the environment variable, OS_RAM_INIT.
A check run can be very helpful in estimating the memory and disk space usage. In a check run, the memory necessary is automatically allocated.
The solver automatically chooses an in-core, out-of-core, or minimum core solution based on the memory allocated. A solution type can be forced by defining the –core option in the run script, OptiStruct then assigns the memory necessary for the specified solution type.
Please see the Memory Limitations for OptiStruct section for detailed information on the following topics: 32-bit versus 64-bit computations, virtual versus physical memory, and automatic memory allocation versus fixed memory runs.
Summary Information for OptiStruct
OptiStruct always creates an .out file which contains summary information for the job. This information can be echoed to the screen through the inclusion of the SCREEN I/O option in the input data or through the use of the -out command line option (see Options for Running OptiStruct).
This file also contains memory and disk space estimates. The disk space estimates for eigenvalue analyses (normal modes, linear buckling, modal methods of frequency, and transient response) are sometimes very conservative and can be three times as much as is truly used. This is because it is not fully predictable how much data needs to be saved to scratch files.
The true usage of memory and disk space is reported at the bottom of the file after OptiStruct has finished.
Should the job be re-run in the same location, the .out file is not overwritten, but is instead moved to _#.out, where # is the lowest available three digit number that creates a unique file name.
For example, if filename.fem were run in a directory already containing filename.out, the existing filename.out would be moved to filename_001.out, and the summary information for the new job would be written to filename.out. Should the job be repeated again, the existing filename.out would be moved to filename_002.out, and the summary information for the latest job would be written to filename.out.
filename.out is the only file that is saved in this manner. All other results files will be overwritten.
Recommendations
Try running OptiStruct with the default setting first (without specification of the –len or –core options).
Do a check run before submitting large jobs (>500,000 dof) to NQS to make sure sufficient NQS memory is being provided. The –lM option can be used to change the NQS memory. Be sure to include at least 12Mb for the executable in addition to the memory necessary to solve the problem. A check run can also assist in debugging input data without having to wait in a queue.
How do I…
Run OptiStruct from HyperMesh using the solver panel
Run OptiStruct from HyperMesh using the OptiStruct panel
Go To
See Also
The HyperWorks Installation Guide