Why not build on top of Java?

[dapz]

There are many java matrix libraries available. Why not simply build on top of one of those?

Yes, now you must use JRuby instead of C Ruby. However, you can build the library more quickly, gain critical mass for later building the CRuby version, etc.

[translunar]

If this is something you're interested in doing, you should do it. None of us know Java, though, and we do know C. So there's that. =)

[dapz]

I don't really know Java either. But I don't really have to; effectively this reduces the problem to just providing thin wrappers around Java libraries.

This saves a lot of time, I think (in terms of getting a functional, performant library up.)

[translunar]

This is the approach we're taking with the distribution gem and much of statsample, I believe. However, we want the interface for the different matrix types to be the same, and that's more complicated.