Re: [digester] Annotations handled multiple times
Hi Lars, please apologize for the late reply - could you please submit a testcase that proves the bug and fill an issue on JIRA? Many thanks in advance, all the best! -Simo http://people.apache.org/~simonetripodi/ http://simonetripodi.livejournal.com/ http://twitter.com/simonetripodi http://www.99soft.org/ On Tue, Apr 30, 2013 at 6:13 PM, Lars Francke lars.fran...@gmail.com wrote: Hi, I'm using the Digester Annotations and everything works pretty well (looking forward to 3.3 for DIGESTER-174). We have a model where we share a contact class and have that annotated with an @ObjectCreate.List because it can live under multiple different elements and a tree-like structure where the top level element contains other elements that in turn have contacts. Here's a simplified version of the schema: A(/a) has B(/a/b) A(/a) has C(/a/c) B has D(/a/b/d + /a/c/d) C has D(/a/b/d + /a/c/d) The problem now is that the AnnotationHandler processes the D element multiple times because it's being reached through multiple branches of the tree, thus creating multiple instances of the ObjectCreateRule which are all fired and obviously screw up the stack. To me this seems like a bug and the AnnotationHandlers should check if they have already visited an element. I'm happy to file a JIRA but I wasn't sure if this might not be intended behavior for some reason I don't understand yet. Also: I might be completely wrong in my diagnosis of this problem. Any help is greatly appreciated. Cheers, Lars - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
Matrix exponential?
Hi folks, I'm looking at a few linear algebra libraries for a Java project. I need to implement clustering of a graph whose edge weights come from a matrix exponential. I've noticed that, of the three major math libraries I've found available in Java (JBLAS, Colt, Commons Math), only JBLAS offers a matrix exponential function expm() similar to what is in Matlab. Unfortunately, JBLAS appears to be dormant and does not have Win64 support, which is going to be a problem for 80% of users. I'm curious why this hasn't been included yet in Commons Math, or whether there are plans to include it any time soon. Has anyone else found a portable solution, short of writing the algorithm? This project will involve control systems and a matrix exponential will be an important part of the toolkit. Thanks! Mike - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
Re: Matrix exponential?
I think I am under informed here. Isn't the matrix exponential normally computed using eigen decomposition? It seems from the series expansion that all that is involved is to exponentiate the diagonal in the eigen vector form. Sent from my iPhone On May 28, 2013, at 11:18, Michael McCormick mmccorm...@runbox.com wrote: Hi folks, I'm looking at a few linear algebra libraries for a Java project. I need to implement clustering of a graph whose edge weights come from a matrix exponential. I've noticed that, of the three major math libraries I've found available in Java (JBLAS, Colt, Commons Math), only JBLAS offers a matrix exponential function expm() similar to what is in Matlab. Unfortunately, JBLAS appears to be dormant and does not have Win64 support, which is going to be a problem for 80% of users. I'm curious why this hasn't been included yet in Commons Math, or whether there are plans to include it any time soon. Has anyone else found a portable solution, short of writing the algorithm? This project will involve control systems and a matrix exponential will be an important part of the toolkit. Thanks! Mike - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
Re: Matrix exponential?
Hi Ted, You are not under-informed, but there is a strong possibility that I am. There are of course many ways to compute the exponential of a matrix, the Schur decomposition and eigendecompositions among them. The algorithm implemented by Matlab's expm() uses a Pade approximation and a square-and-rescale technique that is supposedly faster and numerically very robust. On May 28, 2013, at 3:28 PM, Ted Dunning ted.dunn...@gmail.com wrote: I think I am under informed here. Isn't the matrix exponential normally computed using eigen decomposition? It seems from the series expansion that all that is involved is to exponentiate the diagonal in the eigen vector form. - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
Re: Matrix exponential?
Ah... of course. Diagonalization is not always possible. Never mind. On Tue, May 28, 2013 at 1:03 PM, Michael McCormick mmccorm...@runbox.comwrote: Hi Ted, You are not under-informed, but there is a strong possibility that I am. There are of course many ways to compute the exponential of a matrix, the Schur decomposition and eigendecompositions among them. The algorithm implemented by Matlab's expm() uses a Pade approximation and a square-and-rescale technique that is supposedly faster and numerically very robust. On May 28, 2013, at 3:28 PM, Ted Dunning ted.dunn...@gmail.com wrote: I think I am under informed here. Isn't the matrix exponential normally computed using eigen decomposition? It seems from the series expansion that all that is involved is to exponentiate the diagonal in the eigen vector form. - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
