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Function declaration: example that computes the multivariate normal probability density: | Function declaration: example that computes the multivariate normal probability density: | ||
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The file with the code above can be downloaded from the link below: | The file with the code above can be downloaded from the link below: | ||
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== Homework #1 related functionality == | == Homework #1 related functionality == | ||
Revision as of 23:01, 11 March 2008
Here you can find relevant information on how to implement Pattern Recognition projects using Scilab.
Contents
Brief Introduction to Scilab
Scilab [1] is a open-source Matlab-like tool developed at INRIA. It can be downloaded for several platforms from the link:
http://www.scilab.org/download/
Tutorials describing how to use Scilab can be found here:
- The official documentation[2]
- A hands-on tutorial [3]
- `ANU Scilab Tutorial [4]
- `Une introduction a Scilab [5] , if you want to have some fun reading a Scilab tutorial in French.
Random Number Generator: grand is the function used to generate random numbers. In order to generate a multivariate normally distributed sequence of *n* vectors with mean *mu* and covariance *cov*, grand should be called as:
numbers = grand(n, 'mn',mu, cov);
Function declaration: example that computes the multivariate normal probability density:
// function to compute the multivariate normal distribution //note that it asks for the sigma inverse, as well as the Sigma's determinant function [g] = MultivariateNormalDensity(x,mu, sigma_inv, sigma_det) d=length(x); r2 = (x-mu)'*sigma_inv*(x-mu); factor = 1/sqrt(((2*%pi)^d)*sigma_det); g = factor * exp (-(1/2)*r2); endfunction
The file with the code above can be downloaded from the link below:
- Random Number Generator: grand is the function used to generate random numbers. In order to generate a multivariate normally distributed sequence of *n* vectors with mean *mu* and covariance *cov*, grand should be called as:
numbers = grand(n, 'mn',mu, cov);
Function declaration: example that computes the multivariate normal probability density:
// function to compute the multivariate normal distribution //note that it asks for the sigma inverse, as well as the Sigma's determinant function [g] = MultivariateNormalDensity(x,mu, sigma_inv, sigma_det) d=length(x); r2 = (x-mu)'*sigma_inv*(x-mu); factor = 1/sqrt(((2*%pi)^d)*sigma_det); g = factor * exp (-(1/2)*r2); endfunction
The file with the code above can be downloaded from the link below:
!`MultivariateNormalDensity.sci`__
__ MultivariateNormalDensity.sci
- Random Number Generator: grand is the function used to generate random numbers. In order to generate a multivariate normally distributed sequence of *n* vectors with mean *mu* and covariance *cov*, grand should be called as:
numbers = grand(n, 'mn',mu, cov);
- Function declaration: example that computes the multivariate normal probability density:
// function to compute the multivariate normal distribution //note that it asks for the sigma inverse, as well as the Sigma's determinant function [g] = MultivariateNormalDensity(x,mu, sigma_inv, sigma_det) d=length(x); r2 = (x-mu)'*sigma_inv*(x-mu); factor = 1/sqrt(((2*%pi)^d)*sigma_det); g = factor * exp (-(1/2)*r2); endfunction
The file with the code above can be downloaded from the link below:
!`MultivariateNormalDensity.sci`__
__ MultivariateNormalDensity.sci
Tool Boxes
There are several *tool boxes* of functions written by people all over the world adding extra functionality to Scilab. Here are some useful links:
- `Toolboxes for Scilab and Their Manuals <http://www.scilab.org/contrib/index_contrib.php?page=download&category=MANUALS>`_
- `Scilab Toolbox especialized on Pattern Recognition -- Presto-Box <http://www.scilab.org/contrib/index_contrib.php?page=displayContribution&fileID=194>`_
- `Manual for Presto-Box -- Scilab <http://lmb.informatik.uni-freiburg.de/lmbsoft/presto-box/presto-box-docu.pdf>`_
- `ANN - Neural Networks Tool Box <http://dir.filewatcher.com/d/Mandrake/10.2/src/Sciences/Mathematics/scilab-toolbox-ANN-0.4.2-4mdk.src.rpm.27699.html>`_
- `SCIsvm <http://www.informatik.uni-freiburg.de/~fehr/scisvm.html>`_ , a plugin for the libsvm C++ library.
Scilab Code
All the relevant code for the EE662 course written in Scilab is posted below:
!`MultivariateNormalDensity.sci`__ - Implementation of a function to compute the multivariate normal density
__ MultivariateNormalDensity.sci
