IMPORTANT INFORMATION
Please note that as of 24th June 2002 the Pseudospectra GUI has been
superseded by EigTool; all existing functionality
has been preserved in the new package, which now incorporates MATLAB's
eigs command directly, allowing the user to visualise the convergence
of eigenvalues during the iteration. Many new pseudospectra features have also
been added, including over 30 Demos of pseudospectra applications and the
ability to view transient behaviour in ||A^k|| and ||e^{tA}||.
Download the Pseudospectra GUI
To obtain the Pseudospectra GUI, follow the instructions
below. This is the complete release, which works for both dense matrices and sparse matrices (both directly, and via
eigs). The following code has been written and tested with
MATLAB versions 5.3 and 6; the code available here will not work with
previous versions of MATLAB. However, a version of the GUI which works
with MATLAB 5.2 is available by emailing the author directly.
If you have any requests for new functionality or encounter any bugs, please
let me know; any feedback (both good and bad!) is
also most welcome. We would also like to hear from users of the software: if you find
the GUI useful, please email us to let us know
that you have downloaded it.
The Pseudospectra GUI was last updated on 6th March 2002.
-
There are three different types of download available, but you only need one of
these to be able to use the Pseudospectra GUI. The Generic Archive will work on all platforms (and
both MATLAB version 5.3 and MATLAB version 6), but if
you require maximum performance, you should download one of the Platform Specific Archives, which include
compiled MATLAB mex-files. If you intend to use the Pseudospectra GUI
on a network which contains different types of machine, you may wish
to download one of the Full Archives, which contain the
combined contents of all of the other archives.
Step 2
Move the file you have downloaded to the directory
you want to install the software into.
Step 3
Extract the files from the archive (they will be expanded into a directory called psagui):
- For the gzipped-tar file:
gunzip yourarchive.tar.gz
tar xvf yourarchive.tar
- For the zip file:
You will need a utility to decompress the
archive. WinZip is recommended (although pkunzip is also suitable).
Step 4 (MATLAB version 6 only)
[If you are using MATLAB version 5.3, you don't need to do this step. The
pseudospectra GUI cannot be used in conjunction with eigs in
versions of MATLAB before version 6. However, the GUI will still
function fully for direct pseudospectra computation of both dense and
sparse matrices.]
Start MATLAB, change to the directory where you've just
installed the software, and run the setup script for the GUI:
setup_pseudospectra_gui
This setup script copies the contents of the default
eigs.m file into a file (also called eigs.m) kept in
the psagui directory. You need to use this copy of
eigs if you want to compute pseudospectra after running
eigs. The next step will make sure that this is
the case.
[The only difference between the two eigs
functions is the addition of an extra line which calls the
Pseudospectra GUI script.]
Step 5
Add the directory psagui to your MATLAB path by using the
MATLAB command addpath. A directory can be added permanently
to the path by putting the addpath command in a file called
startup.m; see the MATLAB documentation (or this
page of The MathWorks
website) for more information.
Step 6 Test the GUI by running the command
psa(gallery('grcar',32)).
If all has gone as planned, you'll
see the pseudospectra of a Grcar matrix of dimension 32, as shown
below.
Step 7 (small screen users)
If you are running the GUI on a computer with a small screen (for
example on a laptop), the GUI may be too large to fit. A smaller
version of the GUI (with exactly the same functionality) is available
in the following archives. Simply download one of these, and extract
the files into the same location as before, overwriting the old files
with these new ones. [N.B. You must first download and extract
one of the original archives, in
addition to one of these.]
This can be downloaded as either a gzipped-tar file,
psagui_small.tar.gz (4kB),
commonly used on
Unix/Linux machines, or a zip file,
psagui_small.zip (4kB), commonly used on Windows PCs.
Step 8
We would like to hear from users of the software: if you find the GUI useful, please
email us to let us know that you have downloaded
it.
Information on how to start the GUI is given in Using the GUI with Dense Matrices and Using the GUI with Sparse
Matrices, and full documentation is available
here.
If you have any problems downloading, installing or running the
software, please email me.
Recent Version history for the Pseudospectra GUI is available.
A count of the number of hits on this page is maintained using the
 .
Disclaimer
This software package is delivered "as is". The author does not make
representation or warranties, express or implied, with respect to the
software package. In no event shall the author be liable for loss of
profits, loss of savings, or direct, indirect, special, consequential,
or incidental damages.
Pseudospectra GUI home page.
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