Editing Code

==Chaos and fractal contributions and toolboxes==
*Francesco Potortì's fractal programs (Octave, GPL): http://fly.cnuce.cnr.it/software/#fractals

==Econometrics==
*Michael Creel's Econometrics notes and octave files: http://pareto.uab.es/mcreel/Econometrics/ (try the Econometrics/MyOctaveFiles directory too)
* Ludwig Kanzler's Econometric software (much of it adapted to Octave):
**http://www2.gol.com/users/kanzler/index.htm#L.%20Kanzler:%20Software
**Licence: "All rights reserved", Unfree for distributing modified versions

==Communications Toolbox==
OctaveForge now contains a fairly complete implementation of a Matlab R13 compatible communications toolbox http://octave.sourceforge.net/communications/index.html. This includes
*Random signal creation/analysis
*Source coding (Quantization, Compand)
*Block coding (BCH, Reed-Solomon)
*Modulations (QASK, PSK, etc)
*Galois fields of even order [i.e. GF(2^m) ]

With a recent version of the OctaveForge installed (version 20030602 or later), online help is available with the command
 octave:1> comms info

There are still functions missing or with limitations, and the documentation is not complete. You are therefore welcome to send patches.

===Various Communications-Related Octave Code===
*Simulate multipath fading channels: http://zeidler.ucsd.edu/~sct/code/20060112_multipath/
*Signal processing package in [http://octave.sourceforge.net/signal/index.html OctaveForge]
*Wavelets: LTFAT package in [http://octave.sourceforge.net/ltfat/ OctaveForge], see additional documentation in the [http://ltfat.sourceforge.net/doc/wavelets/index.php LTFAT web page]. Try also Wavelab developed by David Donoho et al. at http://www-stat.stanford.edu/~wavelab/. For more information, see [[Wavelab on Octave]].
* Peter Kovesi's functions for computer vision and image processing: http://www.csse.uwa.edu.au/~pk/Research/MatlabFns/

===Data Formats===
A collection of various signal data formats can be found [http://www.dpmi.tu-graz.ac.at/~schloegl/matlab/eeg/ here]. Many formats are supported by the [http://biosig.sf.net/ BIOSIG]-toolbox for Octave and Matlab.

===Speech and Signal Processing Links===
The following packages contain routines that can be made to work with Octave. Sometimes a little effort is required.

*OctaveForge contains a sizable collection of signal and image processing routines
*Alois Schloegl's Time series analysis toolbox is also available at OctaveForge
*Mike Brookes' Voice Box (http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html)
*University of Sheffield's Matlab Auditory and Speech Demos (http://www.dcs.shef.ac.uk/~martin/MAD/docs/mad.htm)
*Malcolm Slaney's Auditory Toolbox (http://rvl4.ecn.purdue.edu/~malcolm/interval/1998-010/)
*Philip Loizou's COLEA speech analysis toolbox (http://www.utdallas.edu/~loizou/speech/colea.htm)
*Levant Arslans's Speech Processing Toolbox (http://cslr.colorado.edu/software/rspl.html)
*John Hansen's Additive noise sources (http://cslr.colorado.edu/software/rspl.html)
*Dennis Brown's SPCtools (ftp://svr-ftp.eng.cam.ac.uk/pub/comp.speech/tools/spctools) has code for AR and ARMA modelling, particularly in the spcline subdirectory (Note that the version at mathworks is slightly older).
*Steve Niu's AUDI (ftp://ftp.mathworks.com/pub/contrib/v4/systemid/audidemo.tar) and Arthur Jutan's recursivels (ftp://ftp.mathworks.com/pub/contrib/v4/control/recursivels.tar) for ARMA modelling. AUDI worked well enough for me with a bit of fiddling. Haven't tried recursivels.
*Peter Assmann's Track Draw (http://www.utdallas.edu/~assmann/TRACKDRAW/trackdraw.html) has code for a klatt synthesizer
*Time-Frequency Tool box (http://www-isis.enst.fr/Applications/tftb/iutsn.univ-nantes.fr/auger/tftb.html) from CNRS & Rice has code for AM/FM modulation amongst other cool stuff
*Christophe Couvreur's octave (ftp://ftp.mathworks.com/pub/contrib/v5/signal/octave.tar) has filterbank stuff. Of course the plotting doesn't work, but with a bit of fiddling, you can get, 1/3 octave and 1 octave filter banks to work.
*Mathworks signal processing contributions directories for Matlab 4 (http://www.mathworks.com/support/ftp/signalssv4.shtml) and Matlab 5 (http://www.mathworks.com/support/ftp/signalssv5.shtml)
*University of Vienna's Linear Time-Frequency Toolbox (http://www.univie.ac.at/nuhag-php/ltfat)

The following used to be available:

*Kuo, et. al.'s Speech Signal Processing and Recognition tools (SSPR). A number of the other tools are archived at the same site (http://www.eeng.dcu.ie/~speech5/matspeech.html).

Other Software:

*ESPS has been open sourced (BSD license) and is available at http://www.speech.kth.se/software/. Finally we will have a decent pitch tracker!

==Digital communications in medicine (DICOM)==
There is a DICOM package hosted on sourceforge: [[dicom | more information]].

==Adding a quadl like integrator to octave==

quadl is an adaptive quadrature function available in MATLAB (from version 6 I think). It is very fast and accurate and surprisingly it's a small m-file. The algorithm is based on works by Prof. Walter Gander.

Prof. Gander has two m files in his web page http://www.inf.ethz.ch/personal/gander/ which implement his algorithm along with a paper describing the algorithm.

I have not delved deeply into the subject, but the adaptlobe.m function looks equivalent to quadl. Compatibility with MATLAB could be achieved by writing a small quadl wrapper function which simply calles adaptlobe, or by changing adabtlobe's name to quadl.

I have contacted Prof. Gander to allow for distribution of his m-files in octave-forge.

quadl, from the above source is now incorporated into octave-forge-2004-02-12. 

==Model transformation tools==
http://mtt.sourceforge.net

A set of tools for modelling dynamic physical systems using the bond-graph methodology and transforming these models into representations suitable for analysis, control and simulation. These tools use, and generate m files for, GNU Octave.

==Optimization==
There is a variety of code in the octave-forge optimization package http://octave.sourceforge.net/optim/index.html

==Parallelism ==
Operating Octave remotely and in parallel
*distributed linear algebra from octave command line via [http://icl.cs.utk.edu/netsolve/index.html GridSolve]
*OctaveForge has a parallel octave, allowing remote commands and data transfer
*OctaveServer allows net connections to Octave
*MPI toolbox for Octave http://atc.ugr.es/javier-bin/mpitb (This is included in a live CD ParallelKnoppix http://pareto.uab.es/mcreel/ParallelKnoppix/ which you can use without installation or configuration)

==Statistics ==
===Statistics Functions===

*[ http://www.maths.lth.se/matstat/stixbox/ Stixbox] supports Octave. It has a variety of functions not available in octave/octave-forge such as bootstrap and jackknife estimators and a variety of qq plots. GPL.

*[http://www.statsci.org/matlab/statbox.html Statbox] has some regression functions which are not in Octave. Don't know license or Octave compatibility.

*[http://pub.ist.ac.at/~schloegl/matlab/NaN/ NaN-toolbox] A statistic-toolbox for Octave and Matlab®. It handles data with and without MISSING VALUES. More background information is provided in [http://pub.ist.ac.at/~schloegl/matlab/NaN/README.TXT README]

*[http://www.cepremap.cnrs.fr/dynare/ Dynare] is a pre-processor and a collection of MATLAB or SCILAB routines which solve non--linear models with forward looking variables. Cannot find any insight about the license terms, but some code is derived work from GPL code, e.g., [https://www.cepremap.cnrs.fr/websvn/filedetails.php?repname=repos+1&path=%2Fdynare_v3%2Fmatlab%2Fkernel_density_estimate.m&rev=6&sc=1]. The code is adapted from Anders Holtsberg's matlab toolbox (stixbox).

===Multivariate kernel density estimation===

*[http://www.ics.uci.edu/~ihler/code/kde.shtml Kernel Density Estimation Toolbox] LGPL

*[http://www.maths.lth.se/matstat/wafo/documentation/wafodoc/wafo/kdetools/index.html wafo/kdetools] GPL

*A google search for epanechnikov at the r-project.org site returns several R packages on this subject. They all should be GPL compatible. [http://www.google.com/search?hl=en&lr=&q=Epanechnikov+site%3Ar-project.org&btnG=Search]

*[http://astrostatistics.psu.edu/statcodes/sc_density.html sc_density]

*[http://www.cs.waikato.ac.nz/~ml/weka/ Weka] is written in Java, again, don't know how difficult... look for a file called LWL.java

*[http://ltilib.sourceforge.net/doc/homepage/index.shtml LTI-Lib] is an object oriented library with algorithms and data structures frequently used in image processing and computer vision. LGPL

==Symbolic==
===Symbolic Manipulation===
Octave is a matrix algebra tool, not a symbolic algebra tool, so it cannot perform symbolic operations, such as finding the derivative of sine(x) with respect to x

 y = derivative('sin(x)','x'); # Not available in Octave

The below mentioned GiNaC will add symbolic functionality to octave.

===Octave interfaces to GiNaC===
There are two Octave interfaces to GiNaC[1] available

*gino -- http://www.sourceforge.net/projects/mtt (download) provides an Octave interface to GiNaC via ginsh 

 octave:1> df = g_diff ( "sin(x)" , "x" )
 df = cos(x)
 octave:2> x = pi; eval ( df );
 ans = -1

*OctaveForge provides direct access to GiNaC in the [http://octave.sourceforge.net/index/navsymbolic.html symbolic package]. Here is a http://wiki.octave.org/wiki.pl?OctaveForgeGNCIntro short tutorial] to get you started.

===Numerical methods===
In some instances, Octave can give reasonable results using numerical methods

*Octave supports numerical derivatives: 

 t = linspace(0,6,100);
 y = sin(t);
 dydt = diff(y) ./ diff(t)
*OctaveForge has other numerical derivative functions.

===Symbolic algebra systems===
Software other than Octave may be more useful for work involving symbolic manipulations

Free software
*Axiom: http://www.nongnu.org/axiom/

*GiNaC/ginsh: http://www.ginac.de

*Maxima: http://maxima.sourceforge.net

*Yacas: http://yacas.sourceforge.net

Non-free software
*Maple: http://www.maplesoft.com

*Reduce: http://www.uni-koeln.de/REDUCE

Note that most of these systems (and Octave!) may be used from within TeXmacs http://www.texmacs.org

A list of some other scientific software is available at http://sal.kachinatech.com/