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From: mwette@mr-ed.jpl.nasa.gov (Matt Wette)
Newsgroups: comp.soft-sys.matlab,comp.answers,news.answers
Subject: comp.soft-sys.matlab FAQ (Frequently Asked Questions)
Followup-To: comp.soft-sys.matlab
Date: 23 Nov 1993 09:31:34 -0800
Organization: Jet Propulsion Laboratory
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Summary: This article includes product notes and answers to frequently asked
user questions about the matrix-oriented environment MATLAB, by The
MathWorks, and products and tools based on or related to MATLAB.
Xref: senator-bedfellow.mit.edu comp.soft-sys.matlab:3103 comp.answers:2776 news.answers:15030
Archive-name: matlab-faq
Last-modified: 1993/11/23
Version: $Id: FAQ.in,v 1.2 1993/11/23 17:24:16 mwette Exp $
This FAQ is maintained by Matt Wette .
The latest version can be retrieved via anonymous ftp from
csi.jpl.nasa.gov [128.149.29.4] as /pub/matlab/FAQ.text (plain text)
or /pub/matlab/FAQ.html (HTML format)
Contributions, corrections and suggestions are welcomed.
Last update: Tue Nov 23 09:26:35 PST 1993
MATLAB Frequently Asked Questions
=================================
SYNOPSIS
General
=======
1) What is MATLAB?
2) What is the charter for the comp.soft-sys.matlab group?
3) What commercially available MATLAB-type environments are sold?
4) What non-commercial MATLAB-type environments exist?
5) Are there any standards for MATLAB-type tools?
6) How can I join a MATLAB user group?
7) Are there any software archives?
8) Are there any publications related to MATLAB?
MATLAB/SIMULINK Product Information
===================================
9) What's new in MATLAB 4.0?
10) How does MATLAB perform on machine X?
11) What is SIMULINK (alias Simulab)?
12) What toolboxes are currently available from The MathWorks?
13) Can I use C and Fortran programs with MATLAB?
14) How do I contact The MathWorks about MATLAB via email?
MATLAB User Questions
=====================
15) How can I change the default window size, colors, etc. in MATLAB 4?
16) How can I import MATLAB graphics into my Framemaker, TeX, etc. document?
17) Is there a topical help function, like `apropos'?
18) Why am I finding all these undocumented functions (like COMET) in MATLAB?
19) Has anybody any information about the matlab function `system_dependent'?
20) How can I get the parser to accept a dummy reference without an error?
21) How do I get the plot command to cycle through line-types?
22) Can I use `dbup' and `dbdown' within a function?
23) Is there a GNU emacs editing mode for MATLAB?
24) What is the sign convention used in MATLAB's FFT routines?
25) Is there any MATLAB software for wavelets?
26) Is there any MATLAB software for fuzzy logic?
27) Is there any MATLAB software for communications?
28) Is there a MATLAB interface to Mathematica?
29) Why was `fsolve' removed from MATLAB Version 4?
30) Are there any published books on, or relating to, MATLAB?
Quick Little MATLAB Hacks
=========================
31) How can I initialize a this low rank matrix easily?
32) How can I load-from or save-to a file whose name is in a string variable?
33) How can I store the result of `!ls *.dat' in a variable?
34) How can I make a variable global from within a function?
MATLAB on the PC
================
35) What can I do when MATLAB tells me there is not enough environment space?
Xmath / MatrixX Product Information.
====================================
36) What is Xmath?
37) Are there any publications related to MatrixX?
38) Are there any e-mail addresses related to MatrixX/Xmath?
39) What other modules are available from ISI?
Xmath User Questions
====================
40) Is it possible to derive new classes in XMath?
General
=======
1) What is MATLAB?
MATLAB is the name used to refer to the class of matrix cal-
culator environments derived from the first, called MATLAB.
MATLAB was developed by Cleve Moler in the late 1970s at the
University of New Mexico and other locations with support
from the National Science Foundation. Since then, many
work-a-likes have been developed or are in development com-
mercially, in government and university labs, and so forth.
The name of the product available from MathWorks is
"MATLAB", not Matlab, Pro-MatLab, etc. Note that MathWorks
holds a registered trademark on the uppercase version of
MATLAB.
In this document, Matlab may refer to the collective set of
MATLAB-based environments or it may refer to the current im-
plementation developed by MathWorks, Inc. In general, these
MATLAB-based environments are not source-language compati-
ble.
2) What is the charter for the comp.soft-sys.matlab group?
The newsgroup 'comp.soft-sys.matlab' is a forum for discuss-
ing issues related to the use of MATLAB, the scientific cal-
culation and visualization package from MathWorks Inc. This
includes discussion of similar software packages which are
also derived from the original `Classic MATLAB', such as
Xmath from Integrated Systems Inc.
Appropriate discussion in the group will include both gen-
eral Matlab issues and platform-specific questions, and dis-
cussion comparing MATLAB to other systems.
3) What commercially available MATLAB-type environments are sold?
In alphabetical order:
`CLAM' from Scientific Computing Associates, Inc.
246 Church Street, Suite 307
New Haven, CT 06510
Tel: 203-777-7442
Fax: 203-776-4074
`Ctrl-C' from Systems Control Technology, Inc.
CAE Systems Department
2300 Geng Road
Palo Alto, CA 94303
Tel: 800-227-1910
Tel: 415-494-2233
Fax: 415-496-6595
`MATLAB' from The MathWorks, Inc.
Cochituate Place
24 Prime Park Way
Natick, MA 01760
Tel: 508-653-1415
Fax: 508-653-2997.
Email: info@mathworks.com
`O-MATRIX' from Harmonic Software, Inc.
12223 Dayton Avenue North
Seattle, WA 98133
Tel: 206-367-8742
Fax: 206-367-1067
Email: harmonic@world.std.com
`Xmath' from Integrated Systems, Inc.
3260 Jay St.
Santa Clara, CA 95054-3309
Tel: (408) 980-1500
Fax: (408) 980-0400
Email: xmath-info@isi.com
4) What non-commercial MATLAB-type environments exist?
In alphabetical order:
`Caesy' is being developed by Matt Wette
(mwette@csi.jpl.nasa.gov) at the Jet Propulsion Laboratory.
This will be released to COSMIC soon. It will provide data
structures, conversion to C-code, and many other features.
See
M.Wette, "Caesy: A Computer-Aided Engineering System"
Proc. 1992 Symp. on Computer-Aided Control System Design
Napa, CA, March 1992
`Mat/C' developed at Lawrence Livermore National Labora-
tories by Don Gavel. This is not publically available.
`Matcalc', by M.Gerberg and E.J. Moore, University of New
South Wales, Australia. It is available via anonymous ftp
from
draci.cs.uow.edu.au in /netlib/matcalc/
csi.jpl.nasa.gov in /pub/matlab/matcalc/
`MaTX', an interpreter and compiler, developed at Tokyo In-
stitute of Technology. See
M. Koga and K. Furuta, "MaTX: A High-Performance Programming
Language (Interpreter and Compiler) for Scientific and
Engineering Computation," Proc. 1992 Symp. on Computer-Aided
Control System Design, Napa, CA, March 1992
`MEDAL' developed at the University of Waterloo by Grantham
Pang (pang@excel2.uwaterloo.ca). This has the same command
language as MATLAB, but includes a knowledge-based expert
system development facility. It is available for academic
and research users via anonymous. You'll need to get a pro-
gram password from the author to operate it (no sources in-
cluded). It's available via anonymous ftp from
excel2.uwaterloo.ca [129.97.86.13] in /pub/
See
Pang, G.K.H.,"Knowledge-based Control System Design", in Recent Advances
in Computer-Aided Control Systems Engineering, Jamshidi, M and Herget,
C.J. (ed.), Elsevier Science Publishers, 1992.
Pang, G.K.H., "A Knowledge Environment for an Interactive Control System
Design Package", Automatica, Vol. 28. No. 3, pp. 473-491, May 1992.
`Octave', written at the University of Texas
(jwe@che.utexas.edu), is available via anonymous ftp from
ftp.che.utexas.edu as /pub/octave/octave-?.?.tar.Z
`RLaB', written by Ian Searle (ians@eskimo.com), is free
software (in the GNU copyleft sense). It is currently
available via anonymous ftp from
csi.jpl.nasa.gov in /pub/matlab/RLaB
evans.ee.adfa.oz.au in /pub/RLaB
5) Are there any standards for MATLAB-type tools?
There is an IFAC/IEEE-CSS Working Group developing standards
and guidelines for these tools. A proposed standard command
language was developed, is described in the document "Com-
mand Language Standard for CACSD Software" and is available
from
Magnus Rimvall
Control Systems Laboratory, GE-CRD
Schenectady, NY 12301
6) How can I join a MATLAB user group?
To join the user group, send your name, affiliation and ad-
dress to:
matlab-users-request@mcs.anl.gov
For European user groups, contact:
France: Alain Baron
phone: 33/1 45 34 23 91
fax: 33/1 45 07 08 06
Germany: Dr. Ingrid Bausch-Gall
phone: 49/89 323 2625
fax: 49/89 323 1063
Sweden: Svante Littmarck
phone: 46/8 15 30 22
fax: 48/8 15 76 35
email: info@comsol.se
Switzerland: Carl Bergstrom
phone: 031/961 70 11
fax: 031/961 12 82
email: comsol@clients.switch.ch
UK: Peter Campbell
phone: +44-223-421920
fax: +44-223-421921
7) Are there any software archives?
Yes. MATLAB User Group software archive contains more than
1MB of user-contributed code. This archive is located on
NETLIB server of Oak Ridge National Laboratories. To learn
more, send following message:
send index
send index from matlab
to:
netlib@ornl.gov
For access from Europe, try the duplicate collection in
Oslo:
Internet: netlib@nac.no
EARN/BITNET: netlib%nac.no@norunix.bitnet
X.400: s=netlib; o=nac; c=no;
EUNET/uucp: nac!netlib
For the Pacific, try netlib@draci.cs.uow.edu.au located at
the University of Wollongong, NSW, Australia.
The MathWorks maintains the archive on the anonymous ftp
server ftp.mathworks.com [144.212.100.10]. This site con-
tains a "best of" copy of the NETLIB archive as well as oth-
er user-contributed, and MathWorks contributed software and
documentation. If you are interested in submitting software
to the archive pick up the file README.incoming from the ar-
chive or send e-mail to drea@mathworks.com
There is a renegade archive at csi.jpl.nasa.gov
[128.149.29.4], in /pub/matlab. This is stocked with a
mish-mash of stuff you may not find on the other archives
(e.g., free MATLAB-look-a-likes).
8) Are there any publications related to MATLAB?
Yes, Math Works Inc. publishes a quarterly magazine called
MathWorks Newsletter, giving info. on products (new ver-
sions, releases, toolboxes), matlab user group, matlab short
courses, related texts etc. To subscribe to the newsletter,
send email with your snail mail address to
subscribe@mathworks.com.
MATLAB/SIMULINK Product Information
===================================
9) What's new in MATLAB 4.0?
from John Little ...
Here's the "high-level" summary of the major new additions:
* Object-based graphics facility
* 3-D color scientific visualization abilities
* Animation
* Sound output capability
* M-file debugging facilities
* Low-level file I/O functions
* Graphical user interface controls (GUI widget set)
* Sparse matrix support
* An improved help system
* Interpreter and graphics speed improvements
* A new External Interface library (MEX-files, engine, MAT-files)
* Better documentation (in the eyes of the beholder, I imagine :-) )
* Lots of other smaller improvements..
10) How does MATLAB perform on machine X?
LINPACK benchmarks in MATLAB (reported by The MathWorks):
machine KFLOPS (LINPACK)
======= ================
Macintosh (8MHz 68000) 3
PC/AT (6.0MHz/80286/EGA) 15
PC/XT (4.7MHz/8088/CGA) 17
AT&T 6300 (8MHz/8086) 29
Macintosh II (68020/68881) 85
MicroVAX II (VMS/D_floating) 140
Macintosh IIcx (68030/68882) 168
HP 9000/Series 350 190
80386/80387 (20MHz, 386-MATLAB) 232
Macintosh IIci (25MHz 68030/68882) 239
VAXstation 3100 (VMS/D_floating) 365
HP 9000/400 (68030) 500
80486-based PC (33M Hz) 1300
HP 9000/425 (68040 chip) 1400
Macintosh Quadra 700 1500
Sun SPARCstation 1 1500
DECstation 3100 1600
SGI Indigo 2400
Sun SPARCstation 2 2900
Convex C1 3700
IBM RS/6000 7000
HP 9000/700 7400
Cray X-MP 71000
Cray X-MP on a 500-by-500 matrix 135000
Other numbers (reported by users):
80486-DX2 PC @66MHz 3121 (k.hari@ieee.org)
11) What is SIMULINK (alias Simulab)?
SIMULINK is an interactive system for the nonlinear simula-
tion of dynamical systems. It is a graphical, mouse-driven
program that allows systems to be modelled by drawing a
block diagram on the screen. It can handle linear, non-
linear, continuous-time, discrete-time, multivariable, and
multirate systems. SIMULINK runs on workstations using X-
windows, under MicroSoft Windows on the PC, and on the Ma-
cintosh. It takes full advantage of windowing technology,
including pull-down windows and mouse interactions. SIMULINK
is fully integrated with MATLAB, and, together with MATLAB
and the Control System Toolbox, forms a complete control
system design and analysis environment.
12) What toolboxes are currently available from The MathWorks?
The following list includes toolboxes currently offered by
The MathWorks. For more info check
ftp.mathworks.com in /pub/product-info
Signal Processing Toolbox.
This is a toolbox for digital signal processing (time series
analysis). It includes functions for the design and
analysis of digital filters, like Butterworth, Elliptic, and
Parks-McClellan, and for FFT analysis (power spectrum esti-
mation). It also includes some 2-dimensional signal pro-
cessing capabilities.
Control System Toolbox.
This is a toolbox for control system design and analysis.
It supports transfer function and state-space forms
(continuous/discrete time, frequency domain). Function for
step, impulse, arbitrary input responses, as well as Bode,
Nyquist, and Nichols plots. Design with root-locus, pole-
placement, and LQR optimal control.
System Identification Toolbox.
This is a toolbox for parametric modelling. Identified
models are in transfer function form (either z-transform or
Laplace transform) and state-space form (e.g., ARMA models
or Box-Jenkins models).
Optimization Toolbox.
This is a toolbox for linear and nonlinear optimization and
supports unconstrained and constrained minimization,
minimax, nonlinear least squares, multi-objective, and
semi-infinite optimization, linear programming, quadratic
programming and the solution of non-linear equations.
Spline Toolbox.
This is a toolbox for working with splines and is typically
used for curve fitting, solution of function equations and
functional approximation.
Robust-Control Toolbox.
This is a toolbox for robust control system design and sup-
ports LQG/loop transfer recovery, H2, H0, and mu- control
synthesis, singular value frequency response, and model
reduction.
Neural Net Toolbox.
This is a toolbox for designing and simulating neural net-
works and supports implementation of the perceptron learning
rule, the Widrow-Hoff rule, and several variations of the
backpropagation rule. Transfer functions included are hard
limit, linear, logistic & hypertangent sigmoid.
Delta Toolbox.
This is a toolbox for analysis using the delta transform, an
approach to unifying continuous and discrete systems theory
without use of the Z-transform. It is available free to
purchasers of "Digital Control and Estimation: A Unified Ap-
proach," by Graham Goodwin and Rick Middleton.
Image Processing Toolbox.
The Image Processing Toolbox provides an environment for im-
age processing and analysis. Images are matrices
(surprised?). Functions include linear and nonlinear
filtering; image restoration; image enhancement; image
analysis and statistics; color, geometric, and morphological
operations 2-D transforms; and 2D FIR filter design and fre-
quency response.
Symbolic Math Toolbox.
The Symbolic Math Toolbox contains functions for symbolic
algebra, exact linear algebra, variable precision arithmet-
ic, equation solving, and special mathematical functions.
Its underlying computational engine is the kernel of Maple.
The Extended Symbolic Math Toolbox augments the functionali-
ty to include Maple programming features and specialized li-
braries.
Statistics Toolbox.
The Statistics Toolbox provides statistical data analysis,
modeling, and Monte Carlo simulation; building-blocks for
creating your own special-purpose statistical tools; and GUI
tools for exploring fundamental concepts in statistics and
probability. Functionality covers descriptive, inferential,
and graphical statistics, and linear models as well as in-
teractive graphics for dynamic visualization of functions,
data, and probability distributions.
13) Can I use C and Fortran programs with MATLAB?
MATLAB's MEX-file facility allows user to use C and Fortran
subroutines as MATLAB m-files. It is also possible to use
MATLAB as a computational engine for C/Fortran subroutines.
14) How do I contact The MathWorks about MATLAB via email?
Here you go ...
* support@mathworks.com technical support
* suggest@mathworks.com product enhancement suggestions
* bugs@mathworks.com bug reports
* doc@mathworks.com documentation error reports
* register@mathworks.com user and product registration
* subscribe@mathworks.com subscribing user registration
* info@mathworks.com sales, pricing, general info.
* netlib@ornl.gov software archive contact
* digest@mcs.anl.gov user group
MATLAB User Questions
=====================
15) How can I change the default window size, colors, etc. in MATLAB 4?
from serr15@liverpool.ac.uk ...
Try something like the following in your `startup.m' file:
set(0,'DefaultFigurePosition',[5 5 505 405])
set(0,'DefaultFigureColor',[0,0,0]) %% N.B this has side effects.
set(0,'DefaultAxesFontName','times')
set(0,'DefaultTextFontName','times')
set(0,'DefaultAxesFontSize',12)
set(0,'DefaultTextFontSize',12)
16) How can I import MATLAB graphics into my Framemaker, TeX, etc. document?
The MATLAB (version 4) print command provides a "-deps" ar-
gument which provides a Encapsulated PostScript file of your
plot. Some people have reported various problems getting
this stuff to work. Some suggestions:
Removing the last line "%%EOF" from the eps-file.
Use the the pstoepsi filter from Doug Crabill
(dgc@cs.purdue.edu).
Use "bbps" and ghostscript. "bbps.shar" is available via
anonymous ftp on "csi.jpl.nasa.gov". You'll need to get
GhostScript from your nearest GNU ftp site.
[This area needs more work :). ed.]
17) Is there a topical help function, like `apropos'?
Yes. The function you're looking for is `lookfor' (in
MATLAB 4).
>> lookfor fourier
FFT Discrete Fourier transform.
FFT2 Two-dimensional Fast Fourier Transform.
IFFT Inverse discrete Fourier transform.
IFFT2 Two-dimensional inverse discrete Fourier transform.
FOURIER Graphics demo of Fourier series expansion.
DFTMTX Discrete Fourier transform matrix.
>>
18) Why am I finding all these undocumented functions (like COMET) in MATLAB?
from Cleve Moler ...
Almost everything in the "demos" directory is not described
in the User's Guide. There are lots of goodies there. In
4.0, the demos are best place to see examples of Handle
Graphics.
There are other undocumented functions in directories other
than demos. Some of them are "worker" functions that are
unlikely to be used directly; they are simply called by oth-
er functions. A few, like COMET and COMET3, were actually
written after the User's Guide had been sent to the printer.
19) Has anybody any information about the matlab function `system_dependent'?
from John Little (w/editing) ...
`system_dependent' is an unpublished function that is used
for a variety of crufty things. It will most certainly
change from time to time and possible even go away complete-
ly. For anybody curious about it, here is what it does in
MATLAB 4.0 on SPARCstations:
system_dependent(1) deals with the MATLAB-ACSL interface. ACSL
is a simulation language that MATLAB can talk
to. See ACSL.M for more information.
system_dependent(2,0) turns off command-line editing.
system_dependent(2,1) turns it back on.
system_dependent(3) is unused.
system_dependent(4,i,j) is used to program the command-line editing
keys. See CEDIT.M for more information.
system_dependent(5) enables core dumps in the event of seg faults.
Normally MATLAB tries to catch seg faults and
"continue".
system_dependent does different things in MATLAB 3.5 and
other platforms.
20) How can I get the parser to accept a dummy reference without an error?
Adopted from post by Jim Tung ...
MATLAB parses code to look for syntax errors. When the
parser encounters a name with 2 or fewer arguments, it lets
them pass since they might be a variable with indices. If
it encounters a name with 3 or more arguments, MATLAB knows
it cannot be a variable, so the error message is returned.
If you don't want the parser to snag the function, specify
one with 2 or fewer arguments.
21) How do I get the plot command to cycle through line-types?
From Chuck Packard ...
MATLAB v4.1 has a an axis property LineStyleOrder for this.
Monochrome users can tell MATLAB to always use white lines
and cycle through their favorite line styles with the com-
mands:
set( 0, 'DefaultAxesColorOrder', [1 1 1] )
set( 0, 'DefaultAxesLineStyleOrder', '-|:|--' )
These commands can be put in your startup.m to always give
you styled lines.
22) Can I use `dbup' and `dbdown' within a function?
Derived from post's of lara@mrisun.med.yale.edu and
jlittle@mathworks.com ...
MATLAB wasn't designed to be used this way. But, if you
don't reference any variables between your calls to `dbup'
and `dbdown' (i.e., you just use `save', `who', `dir', etc),
it should work. Otherwise, you may well run into problems.
If you `dbup' while in a function, you change the workspace
context while continuing execution of the original function.
This means that subsequent references to variables will be
bound to variables in a different workspace. Since the
internal p-code uses integers as variable identifiers, you
will get a random attachment to these different variables.
At best, you'll get random results. At worst you might seg
fault if you exceed the number of available identifiers.
23) Is there a GNU emacs editing mode for MATLAB?
A GNU emacs `matlab-mode' is available via anonymous ftp
from
csi.jpl.nasa.gov as pub/matlab/util/matlab-mode.el
24) What is the sign convention used in MATLAB's FFT routines?
The FFT in MATLAB is defined as sum(x(i)*exp(-j*i*k/N)) and
not sum(x(i)*exp(j*i*k/N)). The first version is tradition-
ally used by engineers, the second version by mathemati-
cians. Since MATLAB was written by an engineer (John Lit-
tle), the engineering approach was used.
25) Is there any MATLAB software for wavelets?
Contact Carl Taswell is working
on a wavelet toolbox. The toolbox and associated papers are
available via anonymous ftp from
simplicity.stanford.edu in /pub/taswell
A newer version should be available soon.
Also, Jeff Kantor is distributing a
wavelet toolbox. It is available via anonymous ftp from
control.cheg.nd.edu in /pub/wavelets/wavetools1_1.tar
The toolbox, rice-wlet-tools-1.1, a collection of MATLAB
"mfiles" and "mex" files for twoband and M-band filter
bank/wavelet analysis, is available via anonymous ftp from
cml.rice.edu in /pub/dsp/{software,papers}
Contact Ramesh Gopinath .
26) Is there any MATLAB software for fuzzy logic?
A.Lotfi has developed a Fuzzy
Inference Systems Toolbox. It is available via anonymous
ftp from
ftp.mathworks.com as /pub/contrib/misc/fuzzy_inference_systems.sh
or /pub/contrib/misc/pc_fuzzy_inference_systems.sh
A Fuzzy-Control Toolbox has been developed by Bernhard
Kaemmpf . Send him
email if you are interested in obtaining the software.
(Sounds like he is willing to give it away.)
Jyh-Shing Roger Jang has provided a
few routines for demonstrating parameterizing membership
functions (MF) and learning in fuzzy inference systems
(FIS). The file fuzzdemo.tar.Z is available via anonymous
ftp from
csi.jpl.nasa.gov in /pub/matlab/contrib/
27) Is there any MATLAB software for communications?
Mehmet Zeytinoglu has written a
MATLAB toolbox for communications. It is available via
anonymous ftp from
ftp.mathworks.com as /pub/contrib/misc/comm_tbx.tar
28) Is there a MATLAB interface to Mathematica?
Yes. WRI has developed a free MATLAB-Mathematica interface.
It is available via anonymous ftp from
mathsource.wri.com as /pub/WhatsNew/matlab2math.tar.Z (Unix)
or /pub/WhatsNew/matlab2math.sea.hqx (Mac)
or /pub/WhatsNew/matlab2math.zip (Windows) ?
or via email via "send 0205-951" to mathsource@wri.com.
29) Why was `fsolve' removed from MATLAB Version 4?
The algorithms used by fsolve were not numerically well
behaved. MathWorks did not feel that it met the standards
require for approved software. The version of FSOLVE in the
Optimization Toolbox is recommended. If your site doesn't
still have the 3.5 version, you can get it via anonymous ftp
from
ftp.mathworks.com as /pub/contrib/optim/fsolve35.tar
30) Are there any published books on, or relating to, MATLAB?
There is a list of published book available via anonymous
ftp from
csi.jpl.nasa.gov as /pub/matlab/matlab-books
Quick Little MATLAB Hacks
=========================
31) How can I initialize a this low rank matrix easily?
Here's "Tony's trick", attributed to Tony Booer of Schlum-
berger:
To initialize a matrix with values "a" in the first row and
values "b" in the second row, do the following:
[a(1,ones(1,m)) ; b(1,ones(1,m))]
32) How can I load-from or save-to a file whose name is in a string variable?
name = 'xyz.mat';
eval(['save ', name]);
eval(['load ', name]);
33) How can I store the result of `!ls *.dat' in a variable?
[stat, list] = unix('ls *.dat');
The variable `stat' contains the return status, the variable
`list' contains the output.
34) How can I make a variable global from within a function?
You can in MATLAB 4. The following hack is from Laura Nee-
dles and Mike Kantner
. Define the script file
`mkglobal.m', containing
function [] = mkglobal(var)
% MKGLOBAL mkglobal(var) - make var a global variable
if ~exist('mkglobal_var'), mkglobal_1; end;
mkglobal_var = var; mkglobal_2
Define the script file `mkglobal_1.m' as
global mkglobal_var
Define the script file `mkglobal_2.m' as
eval(['global ', mkglobal_var]);
MATLAB on the PC
================
35) What can I do when MATLAB tells me there is not enough environment space?
This usually happens if in the matlab path you include
greater that 4 or 5 paths. One solution is to increase your
environment space by adding the following command in your
config.sys file:
shell=c:\dos\command.com /e:nnnnn /p
where nnnnn is the number of bytes you use for environment
memory. It varies from 256 bytes to 32768 bytes(32Kbytes).
Usually, 5000 bytes can solve your problem. (The /p command
is used so that the autoexec.bat file runs when you boot
your computer.)
Xmath / MatrixX Product Information.
====================================
36) What is Xmath?
from mesaros@isi.com ...
Xmath is an interactive mathematics, scripting, and graphics
environment for X Window workstations. It has features
which represent a significant improvement on matlab-type
software tools, including:
* Object-oriented scripting language.
* "Point-and-click" color graphics.
* Visual debugging tool.
* LNX and C-callable libraries.
* Programmable MOTIF GUI layer.
Xmath from Integrated Systems Inc. is available on the In-
ternet via FTP from isi.com. If you would like to down-load
Xmath to view the Xmath Interactive demo, do the following:
From the UNIX/Shell environment, type:
ftp isi.com (if the host is unknown, try ftp 192.73.222.1)
When asked for name/user, type:
anonymous
When asked for the password, simply type your e-mail address.
Once your e-mail address is accepted, and if the maximum
number of ftp clients has not been exceeded, the connection
will be made and a list of instructions will appear. Simply
follow that list of instructions to transfer a copy of Xmath
to your system.
37) Are there any publications related to MatrixX?
Yes, ISI publishes a quarterly magazine called Response
Times that gives information on products (new ver- sions,
releases, modules), user conference, classes, and a Techni-
cal Support Corner where they answer user questions.
Also, ISI has an annual Users Conference. The viewgraph
presentations from this conference are available. The next
conference in March 15-17, 1993.
38) Are there any e-mail addresses related to MatrixX/Xmath?
Yes. Some are:
* support@isi.com tech support for ISI MatrixX products
(408)980-1590 ext. 321
* info@isi.com product literature requests
* kate@isi.com contributions to Response Times Mag
39) What other modules are available from ISI?
* MatrixX/XMath
* Robust Control Module
* Optimization Module
* Model Reduction Module
* Digital Signal Processing Module
* System Identification Module
* System_Build
* RT/Expert System Block
* RT/Fuzzy Logic Block
* Interactive Animation
* AutoCode (C,FORTRAN, Ada)
* Automatic Documentation Generation
3rd Party Packages
* ADAPTx Automated System Identification Software
Real Time Execution
* AC-100 Product for Hardware in the Loop Simulations
ISI recently merge with the Software Component Group that
makes and sells the PSOS+ real time operating system and
development tools.
Xmath User Questions
====================
40) Is it possible to derive new classes in XMath?
From Alexandra Schmidt ...
Xmath does not currently allow you to 'derive' new subc-
lasses from the built-in ones (dynamic systems, parameter-
dependent matrices, strings and string matrices, polynomi-
als, "special matrices", etc.) However, a number of our
users have used the list object to create compound objects
containing different kinds of built-in objects, then used
the resulting list-based object for more complex data model-
ing. Your question echoes a request we've heard a number of
times and is a high priority for our future development, so
keep an eye out. . .
$Id: FAQ.in,v 1.2 1993/11/23 17:24:16 mwette Exp $