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Symbolic
(Statistics)
(Symbolic)
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*[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
*[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/

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