Sam Halliday a écrit : > Just to let you know, I've contacted the author of this blog post... who has > recently written a library called jblas. I've asked him if he wants to be > involved with the initiative here, to consolidate efforts for Java Linear > Algebra packages. > > Incidentally... this blog post references a very pervasive, yet abandoned, > project named Colt. Colt was a brilliant library in its day (now numerically > challenged), although riddled with license issues (depending on > non-commercial and ill-defined not-for-military-use middleware). Colt is a > reminder of what can happen when a great library is written but not > maintained. There might be lessons to learn from their API... I know some > projects that use it. > > It might be worthwhile contacting other Java Linear Algebra package authors, > such as JAMA. JAMA is a very small library in comparison (no additional > functionality over MTJ or commons-math)... but they might have a different > take on APIs than we would have.
JAMA is a deceased project. We have based our API for decomposition algorithms on the JAMA API, with some extensions we thought were useful (see the class javadoc for the various decomposition interfaces). For example, we have added interfaces instead of using only classes and we have added solvers that could avoid building some large intermediate matrices, thus greatly improving speed. We have compared our results to JAMA. Here are some results I just rerun for this message, with dimensions between 600 and 1000. Once again, beware of the single case, single hardware, single trial effect: the bench is most probably biased due to these characteristics. multiplication: about 1.5 times faster with DenseRealMatrix QR decomposition + solve: about 10 times faster at dimension 600, about 20-25 times faster at dimension 1000 eigen decomposition: about 3 times faster at dimension 600, about 6 times faster at dimension 1000 These results could have been expected: JAMA focused on the API, not on the implementation and almost naive implementations have been used with no consideration to the memory handling. So clearly, JAMA is superseded on both the API, maintenance and efficiency aspects. See for example these messages: http://markmail.org/message/a4d454alexugur2m http://markmail.org/message/h2rmq6wo7nwqzx4w http://markmail.org/message/l4cvopambgumrwbs Luc > > > Ted Dunning wrote: >> http://blog.mikiobraun.de/2009/04/some-benchmark-numbers-for-jblas.html >> > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
