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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/ | |||