zhihua li
2005-Mar-26 06:23 UTC
[R] learning networks with a large number of variables andpre-set parents.
I didn't go into details when I asked the question for feat that I would overly specific and blur my real goals. The links between variables are defined as conditional probability distributions. So if the probability distribution of a variable X's value is conditioned on the probability distribution of the values of Y and Z, we say Y and Z are X's parents, and in the network, there are two arrows starting from Y and Z and poining both to X. Clearly it's something like a bayesian network. And I do know some packages, such as deal, can learn the bayesian networks structure from training data. But I'm not sure if deal or other similar packages can handle 10000 variables...... Thanks a lot for your information.>From: "Shelby Berkowitz" <berkowi4 at msu.edu> >To: "'zhihua li'" <lzhtom at hotmail.com> >Subject: RE: [R] learning networks with a large number of variablesandpre-set parents.>Date: Fri, 25 Mar 2005 10:00:17 -0500 > >It's not really clear to me what it is you're trying to do, how you've >defined links between these variables, or how you're defining 'highest >scoring network', but for manipulating a network of that size you might >want to check out Pajek http://vlado.fmf.uni-lj.si/pub/networks/pajek/ >network analysis software - there is probably a way from there to >extract the network you want, and you can export from it back into R for >further analysis. > >HTH, > >Shelby > > >-----Original Message----- > >From: r-help-bounces at stat.math.ethz.ch > >[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Achim Zeileis > >Sent: Friday, March 25, 2005 5:41 AM > >To: zhihua li > >Cc: r-help at stat.math.ethz.ch > >Subject: Re: [R] learning networks with a large number of > >variables andpre-set parents. > > > > > >This is the second time within 24 hours that you cross-posted > >the same question to two of the R mailing lists, please read > >the posting guide linked at the bottom of this mail on how to > >properly ask your questions. > > > >As for your question: I'm not aware of an R package that would > >be able to do what you are looking for, but you might also ask > >the maintainer of the package you're specifically interested > >in for more details. Z > > > > > > > >On Fri, 25 Mar 2005, zhihua li wrote: > > > >> hi netters: > >> > >> I have a series of discrete variables which form a network and I > >> want to learn the network structure from some training data. I could > >> have used packages like deal but there are two problems. > >> > >> First of all, I have 10000 variables. So the possible network > >> structure is awfully huge, I don't know how long it will > >take my PC to > >> find the highest-scoring network..........maybe a month? Secondly, I > >> have some prior knowledge that only 500 out of the 10000 > >variales are > >> possible parents. In another word, only those arrows startting from > >> the 500 variables and pointing to the remaining 99500 variables are > >> allowed in the network. In deal an assignment to "banlist" should > >> help me rule out the impossible arrows. But in my case the number of > >> "impossible arrows" is 500*499+99500*99549, and so the "banlist" > >> would get unacceptable long. Are there any methods (in deal or other > >> packages) to specify the parents set in advance? > >> > >> Thanks a lot! > >> > >> ______________________________________________ > >> R-help at stat.math.ethz.ch mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-help > >> PLEASE do read the posting guide! > >> http://www.R-project.org/posting-guide.html > >> > > > >______________________________________________ > >R-help at stat.math.ethz.ch mailing list > >https://stat.ethz.ch/mailman/listinfo/r-help > >PLEASE do read > >the posting guide! http://www.R-project.org/posting-guide.html > > > >-- > >No virus found in this incoming message. > >Checked by AVG Anti-Virus. > >Version: 7.0.308 / Virus Database: 266.8.1 - Release Date: 3/23/2005 > > > > >