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There's an auxiliary reason to use Octave/MATLAB that most people don't talk about. Vastly cheaper access to high quality linear system solvers. Writing high-

by kxyvr 10y ago

There's an auxiliary reason to use Octave/MATLAB that most people don't talk about. Vastly cheaper access to high quality linear system solvers. Writing high-performing, multicore factorization codes is hard and only a few people do that well. For example, that's been most of Tim Davis' career. Anyway, codes like CHOLMOD are dual licensed GPL/commercial. If I want access to that solver, but I don't want to GPL my code, I can write a Octave/MATLAB routine that uses the `chol` command. Implicitly, this uses CHOLMOD on both Octave/MATLAB, but it's baked into the interpreter. Now, MATLAB has paid the appropriate license for access to the routine, whereas Octave just abides by the GPL. If I deliver a piece of code to a customer that needs this routine, I just tell them they need to use MATLAB because they provide the license cover. If my customer chooses to use Octave instead, that's not my choice. However, even if they do, GPL only kicks in if they externally deliver their code. It's this weird situation where I can legally deliver code because it's fine under the MATLAB license, but the end result will work under Octave, which can be used freely under GPL. Anyway, there are a huge number of solvers where this occurs. Something like Python is fine, but I'd be very careful with the licensing if anyone intends to distribute under a non GPL license since a large number of the good numerical libraries are dual licensed GPL/commercial.

ramshorns 10y ago
That's an interesting effect of dual licensing, but I'm not sure I understand it right. If you write a routine that uses the `chol` command, that's not a derivative work of chol, is it? It's just a function call, which is a normal use. It seems like if you give someone this routine but don't give them CHOLMOD, they can use any implementation of that function signature they wish. But maybe since it's an oct-file (or I imagine a mex-file in MATLAB), it's baked into the interpreter and it's a different story.

by kxyvr 10y ago

ramshorns 10y ago

That's an interesting effect of dual licensing, but I'm not sure I understand it right. If you write a routine that uses the `chol` command, that's not a derivative work of chol, is it? It's just a function call, which is a normal use. It seems like if you give someone this routine but don't give them CHOLMOD, they can use any implementation of that function signature they wish. But maybe since it's an oct-file (or I imagine a mex-file in MATLAB), it's baked into the interpreter and it's a different story.