Matlab vs Scilab Rafael Brunner Whats going on
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: poisson 2 d_kron
Overview (1) • for var = expr, statement; . . . ; statement; end • while expression, statements; end • if expr then statements; else statements; end
Overview (2) • select expr case expr 1 then instructions 1. . . case exprn then instructionsn [else instructions] end
Overview (3) • [lhs, rhs] = argn(0) • error • warning
Example (demo) • poisson 2 d_kron. m poisson 2 d_kron. sci • mfile 2 sci
2 D-Poisson matrix
Sparse matrices • Three different algorithms to generate the 2 D-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 • 2 D-Poisson matrix generated by poisson 2 d_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 - mfile 2 sci
Summary • speed • graphics • signal processing
Is Scilab an alternative to Matlab?
In my opinion: Scilab is capable and can be an alternative to Matlab.
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