Matlab vs. Scilab by Vikcyb7

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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.

								
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