Matvec Users’ Guide

Chapter 14
Exception
Exceptions in Matvec
14.1 Error Handling
Matvec does not handle errors very gracefully. You will be forced to quit Matvec if the number of errors
reaches 15 in a session.
After numerous errors, you may find that Matvec behaves unexpectedly, then you REALLY have to quit
the current session immediately and restart it again.
14.2 Troubleshooting
14.2.1 Lack of memory
Because Matvec allocate memory dynamically for each object. If you get a message saying “lack of memory”,
then you have reached the maximum memory in your computer.
14.2.2 Intermediate files
Matvec may automatically swap data from the computer memory to disk. These intermediate files are saved
in the $(HOME)/.matvec directory with file names something like 798233981.2 where 798233981 is your
computer system time when you launched Matvec, and 2 indicates that this is the second intermediate file
since you launched Matvec. It is clear that you are safe to launch multiple Matvec sessions within the same
directory as long as those sessions started at different time. All of these intermediate files are automatically
deleted whenever Matvec is normally ended; otherwise you have to manually delete them.
14.2.3 Bugs
• Whenever you get a message similar to “you have probably found a bug!”, report to Matvec maintainer
with your script and data.
• Whenever you suspect a bug, don’t report it until you can duplicate the bug.
14.2.4 EPSILON
• if you get a message similar to
***ERROR***
SparseMatrix seems not positive (semi)definite: -3284690426.413546
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