Sujit, What do you think the trade-offs are between the representation that you used and another one where you have a Map<int, SparseVector> that contains rows or columns?
On Mon, Dec 1, 2008 at 1:40 PM, Sujit Pal <[EMAIL PROTECTED]> wrote: > Hello, > > I am a new, but fairly happy user of commons-math 1.2 and I have begun > to use it in my code. I needed a sparse matrix implementation for some > data analysis work I was doing, and unfortunately the code with > RealMatrixImpl was coming back with an OOME. So I built a > SparseRealMatrixImpl as a subclass of RealMatrixImpl, which uses a > Map<Point,Double> as its backing store, storing only the non-zero > entries. I would like to contribute this implementation back to the > commons-math project. > > I have opened a JIRA enhancement request MATH-230 with a patch against > the 2.0 branch. Patch and detailed description of the changes are > available here. > http://issues.apache.org/jira/browse/MATH-230 > > I have also had to make some changes to RealMatrixImpl and > LUDecompositionImpl, mainly replacing the data[][] references with > RealMatrix.getEntry(i,j) calls to insulate the backing store from being > accessed directly by calling code, and thus making it possible for > subclasses to provide their own internal backing stores. > > Would appreciate if you folks can take a look and let me know if it is > feasible to add this into the 2.0 release. That way I can continue using > commons-math future versions without having to patch it after every > upgrade. > > I noticed that there has been some previous discussion about sparse > matrix support here: > http://markmail.org/message/2k5dk4fbewdtn5rz > so I sent a personal email to John Iacona asking him about about the > code he speaks of here. But he is working on other things, and doesn't > know when he will be able to check in his sparse matrix support changes. > His approach is a little different from mine (he has a SparseMatrix > interface, which is implemented by a SparseMatrixImpl). I considered > that approach initially, but came to the conclusion that it would mean > quite a bit of code duplication, which I wanted to avoid as far as > possible. > > Thanks > -sujit > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > -- Ted Dunning, CTO DeepDyve 4600 Bohannon Drive, Suite 220 Menlo Park, CA 94025 www.deepdyve.com 650-324-0110, ext. 738 858-414-0013 (m)
