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Matlab vs. Scilab
Rafael Brunner
What‘s going on?
• Few words about Scilab‘s origin• Introduction to Scilab:
- linear algebra- programming
• Parts of my term work:- sparse matrices- Savitzky-Golay filter- performance comparison
• My own experiences
Scilab
• developed since 1990 at INRIA / ENPC (France)
• open source• free of charge• high quality toolboxes available
- artificial network- serial port
• similar to Matlab... yes, but...
Demo
• Linear Algebra- basics (how to enter matrices etc.)- compute with matrices- solving systems of equations- hessenberg form- LU-, QR-decomposition- eigenvalues, -vectors- SVD
Programming
• introduction / overview• example: poisson2d_kron
Overview (1)
• for var = expr, statement; ...; statement; end
• while expression, statements; end• if expr then statements;
elseif expr then statements;else statements;end
Overview (2)
• select expr case expr1 then instructions1 ... case exprn then instructionsn [else instructions]end
Overview (3)
• [lhs,rhs] = argn(0)• error• warning
Example (demo)
• poisson2d_kron.m poisson2d_kron.sci• mfile2sci
2D-Poisson matrix
Sparse matrices
• Three different algorithms to generate the 2D-Poisson matrix:- set the elements one by one- block wise- kronecker product
Performance comparison
Solving a system Ax=b
• in this case Ax = 1• pcg (preconditioned conjugate
gradients method)• Scilab does not provide a pcg
method Scilin (IRISA)
Demo
• Solving Ax=1 for n=100• 2D-Poisson matrix generated by
poisson2d_kron
Performance comparison
Savitzky-Golay Filter
• measured data (slowly varying and corrupted by random noise)
• reconstruction of the underlying smooth function
Savitzky-Golay Filter (DEMO)
My own experiences
• editor• translating
- build up new functions- mfile2sci
Summary
• speed• graphics• signal processing
Is Scilab an alternative to Matlab?
In my opinion:Scilab is capable and can be
an alternative to Matlab.