Free Edition of ALGLIB is targeted at scientists, researchers and engineers who do not want to buy commercial license. It is delivered for free under GPL 2+ terms and offers full set of functionality - same as in commercial edition of ALGLIB. However, there are two important limitations in the Free Edition of ALGLIB.
First limitation is performance. Free Edition does not include multithreading functionality, low level optimizations and integration with Intel MKL. Free Edition of ALGLIB for C# is 100% C# assembly, while Commercial ALGLIB for C# includes both 100% managed version - and its high performance native replacement with identical C# interface. It is good on small and medium-scale computational problems, but may be too slow on large-scale ones.
Second limitation is license. GPL license, which is used by Free Edition of ALGLIB, is not good for most commercial applications. It allows free use and free modification of ALGLIB, but any derivative work (i.e. application using ALGLIB) must be distributed under GPL license too (copyleft requirement). It is good for those who just wants to solve some computational problem or to use ALGLIB in other GPL projects. However, copyleft requirement is not good for commercial users. Basically, it means that you a) must distribute your program along with source code and b) can't restrict your users from copying your program, reselling copies or distributing them for free.
Here is table which compares ALGLIB editions:
|Free Edition||Commercial Edition|
|Portability||x86, x64, ARM.
|User can see/modify source code||Yes|
Pure C# computational core.
Managed and native cores.
Generic C++ code.
SSE support (on x86/x64).
Intel MKL (optional).
|Target audience||Open source developers.
If you are satisfied by both performance and license of the Free Edition, you can download and start using it right now (see downloads section below). However, if you need better performance or commercial license, you may consider buying Commercial Edition.
|alglib-3.8.2.csharp||zip||tgz||C# version (100% managed code)|
|alglib-3.8.2.vbnet||zip||tgz||VB.NET wrapper for C# version|
|alglib-3.8.2.cpython||zip||tgz||CPython wrapper for C++ version (can be used from Python 2.x and 3.x)|
|alglib-3.8.2.ipython||zip||tgz||IronPython wrapper for C++ version|
|Pre-3.x releases are not compatible with 3.x branch;|
however, they will be there for languages which were not ported to 3.x yet
|alglib-2.6.0.mpfr.zip||Multiple precision version (MPFR)|
ALGLIB® - numerical analysis library, 1999-2013.