In the real world, omissions and mistakes in programming logic are inevitable. When performing an analysis and an un-trapped error occurs, a general Fortran message is given, and the analysis stops. For example, forrtl: severe (605): illegal structure for unformatted file.
In most cases, the error message are not helpful since the Fortran messages are intended for the program developer, and a workaround may not exist. In some cases though, it may be possible to make an educated guess about why the error occurred based on the error message and the additional insight below. Then by adjusting the input, you can avoid the error and get results.
Whether you are able to bypass the problem or not, an archive of the original model should be created and sent to technical support along with any description that will help to identify the problem. See the page Getting Started: Starting Autodesk Simulation:for details. If possible, create the archive with results (so that all files are included). If the archive with results is too large, then send the archive of the model only, but also send the log files. (See the page Setting Up and Performing the Analysis: for a list of files and their locations.)
The following table gives some of the more common error numbers (out of the hundreds possible). The first column lists error numbers returned by the processor.
The first line of the second column provides the message as it is displayed (following forrtl:), including the severity level, message number, and the message text. The following lines of the second column contain an explanation of the message (from the vendor's Fortran manual) and any known clarification specific to Autodesk Simulation.
|Number||Severity Level, Number, and Message Text; Explanation|
severe (9): permission to access file denied
Check the permissions of the specified file and confirm that the file can be created or written to? Are the file properties set to read only? Next, check the permissions of the folder where the file is located and confirm that the folder is not set to Read only.
As another test, log into the computer using a login with full administrator privileges.
severe (22): Input record too long
A record was read that exceeded the explicit or default record length specified when the file was opened.
In some cases, a temporary file can be too big if the allocated memory is too high. Try allocating less memory which will create more but smaller temporary files. (The allocated memory is set somewhere under the Setup Model Setup Parameters dialog.)
severe (24): End-of-file during read
Generally, this error message also includes a unit number, which is usually a temporary file. For example, end-of-file during read, unit 76 indicates a problem with the .t76 file. The software expected the file to be longer than it is.
In some cases, a problem with the model setup or input will cause the file to be 0 bytes long, so trying to read the file later results in this error.
Another source of the problem is when the file does not exist.
severe (29): File not found
A file with the specified name could not be found during an open operation. If the file is a user-specified file, make sure it exists in the proper folder.
severe (43): File name specification error
A pathname or file name given to an OPEN or INQUIRE statement was not acceptable. The problem may also be related to lack of disk space.
severe(157): Program Exception - access violation
The program tried to read from or write to a virtual address for which it does not have the appropriate access, such as a read-only or protected address of memory.
Your model solution size may have exceeded your computer limits. Reduce the model size or provide more free disk space on the computer drive where the TEMP directory resides, or increase your computers RAM. If this doesn't avoid the problem, then the problem may be caused by another fault.
The folders under which the model is saved or the filename itself may have an illegal character. Try saving the model to a different folder closer to the root, and different filename. Keep the folder names and filename short, and use only letters and numbers.
severe(159): Program Exception - breakpoint
The Fortran RunTime Library has encountered a breakpoint in the program.
One source of this problem is when file sizes become very large. Reduce the size of the model or the frequency that results are output. For example, in a transient heat transfer analysis, output fewer time steps so that the result files are smaller.
severe(164): Program Exception - integer divide by zero
During an integer arithmetic operation, an attempt was made to divide by zero. Locate and correct the source code causing the integer divide by zero.
In an extreme case, the model may be too small! For example, modal analysis requires more degrees of freedom in the solution than number of modes being solved. If a test model has only a few free nodes (others may be restrained), the modal analysis may not solve.
severe(168): Program Exception - illegal instruction
The program tried to execute an invalid instruction. This is an operating system error.
severe(170): Program Exception - stack overflow
The Fortran RunTime Library has detected a stack overflow while executing your program.
The model may be too large.
severe (605): Illegal structure for unformatted file
The file was opened with a format specified, but its internal physical structure was incorrect or inconsistent. Possible causes: the file was created in another mode or by a non-Fortran program.
Alternatively, one of the temporary files created by the processor (.t*, located in the modelname.ds_data folder), may be larger than the limit. For example, the file may be larger than 2 GB.
severe (613): End of file encountered
The program tried to read more data than the file contains.
severe (620): Too many bytes read from unformatted record
The program tried to read more data from an unformatted file than the current record contained. If the program was reading from an unformatted direct file, it tried to read more than the fixed record length as specified by the RECL option. If the program was reading from an unformatted sequential file, it tried to read more data than was written to the record.