HP MLIB User's Guide Vol. 2 7th Ed.

650 HP MLIB User’s Guide
Troubleshooting
Troubleshooting
Here are some suggestions to help you find the cause of a problem:
1. Verify that the subprogram usage in the program matches the subprogram
specifications in the documentation. Pay attention to the number of
arguments in the CALL statement and to the declarations of arrays and
integer constants or variables that describe them. Write out all the
arguments immediately before and after the CALL statement.
2. Make sure there really is a problem. For example, if an apparently incorrect
answer is being computed, check to see if the answer does satisfy the
problem as defined in the program. Also, for problems with more than one
answer, LAPACK may produce a different answer or give the answers in a
different order than expected. If the problem is ill-conditioned, LAPACK
may not be able to compute a reliable answer. Error messages often suggest
the cause of the problem.
3. Isolate the problem. If possible, write a small test program that encounters
the same difficulty. For example, write the data causing the problem from
the original program into the small one. In this way, you eliminate
extraneous code from suspicion. If the problem area is large, try to pare it to
a manageable size. For example, if a 50-by-50 linear system fails, try to
produce a 2-by-2 system that fails in the same way.
HP MLIB man pages
HP MLIB man pages are installed in /opt/mlib/share/man. Set this path in your
MANPATH environment variable to access man pages.
HP MLIB provides LAPACK man pages that contain:
• An introduction to LAPACK (lapack(3m))
• An introduction to each group of subprograms
• A reference page for each subprogram. HP MLIB is compliant with
LAPACK 3.0—man pages for HP LAPACK subprograms are those provided
with version 3.0 of the public domain LAPACK
For further explanation and a table of contents of reference entries for
LAPACK, refer to the lapack(3) man page.