marohnicluka / giac

contributions to Giac computer algebra system

My contributions to Giac/Xcas computer algebra system, including the support for:

• graph theory (a comprehensive package containing over 200 commands, see doc/graphtheory-user_manual.pdf for details)
• signal processing and audio (creating wave files, convolution and (auto)correlation, filtering, windowing, resampling, noise removal)
• images
• continuous and short-time Fourier transform
• continuous and discrete Hilbert transform
• analytic signal representation
• empirical mode decomposition
• Hilbert-Huang transform
• constrained optimization in multivariate calculus (local and global extrema)
• calculus of variations
• numerical differentiation (Fornberg's algorithm)
• (mixed integer) (non)linear programming
• transportation problems
• curve interpolation and fitting (Thiele's algorithm, Floater and Hormann's algorithm, trigonometric polynomial fitting, Remez algorithm, L^2 polynomial approximation)
• B-splines with efficient fitting to data
• simplification of trigonometric expressions
• statistics (discrete random variables with sampling, kernel density estimation, maximum-likelihood fitting)
• ordinary differential equations (an implementation of Kovacic's algorithm and a second-degree boundary value problems solver)
• Diophantine equations
• K-means and hierarchical agglomerative clustering
• feed-forward neural networks
• LaTeX/MathML/TeXmacs conversion of Giac output
• colors and colormaps
• using Giac in TeXmacs

giac's Issues

Licensing

Hello,
I came to find this page through my search for a program that can do continuous Fourier Transform on the HP Prime calculator. The calculator uses a subset of XCas/Giac for is CAS. I was excited when I realized that you had implemented Fourier Transform for the Xcas and I tried it on the windows application and it worked just as expected.

I contact the HP development team and asked if they could add fourier and ifourier to the Prime. As I already mentioned, not all XCas functions make their way to the Prime. I was told that they could not add fourier and ifourier due to the way you licensed your code and the fact that the Prime's OS is not open source. They told me the only way they can include those two functions (and possibly some of the others that you've coded) is for you to change your licensing to allow your code to be used in a commercial product like the prime. So, I'm here hoping that you can somehow be persuaded to change your licensing and allow the Prime team to add your implementation of FT to the prime. I'm studying electrical engineering and having the ability to do FT, convolution, correlation, etc, on the calculator is massive. I'm sure many others would be appreciative if you could allow your code to be used on the Prime.

Thanks.