> From: Weiwei Shi > > it works. > thanks, > > but: (just curious) > why i tried previously and i got > > > is.vector(sample.size) > [1] TRUE
Because a list is also a vector: > a <- c(list(1), list(2)) > a [[1]] [1] 1 [[2]] [1] 2 > is.vector(a) [1] TRUE > is.numeric(a) [1] FALSE Actually, the way I initialize a list of known length is by something like: myList <- vector(mode="list", length=veryLong) Andy > i also tried as.vector(sample.size) and assigned it to sampsz,it still > does not work. > > On 7/7/05, Duncan Murdoch <[EMAIL PROTECTED]> wrote: > > On 7/7/2005 3:38 PM, Weiwei Shi wrote: > > > Hi there: > > > I have a question on random foresst: > > > > > > recently i helped a friend with her random forest and i > came with this problem: > > > her dataset has 6 classes and since the sample size is > pretty small: > > > 264 and the class distr is like this (Diag is the > response variable) > > > sample.size <- lapply(1:6, function(i) sum(Diag==i)) > > >> sample.size > > > [[1]] > > > [1] 36 > > > > > > [[2]] > > > [1] 12 > > > > > > [[3]] > > > [1] 120 > > > > > > [[4]] > > > [1] 36 > > > > > > [[5]] > > > [1] 30 > > > > > > [[6]] > > > [1] 30 > > > > > > I assigned this sample.size to sampsz for a stratiefied sampling > > > purpose and i got the following error: > > > Error in sum(..., na.rm = na.rm) : invalid 'mode' of argument > > > > > > if I use sampsz=c(36, 12, 120, 36, 30, 30), then it is > fine. Could you > > > tell me why? > > > > The sum() function knows what to do on a vector, but not on > a list. You > > can turn your sample.size variable into a vector using > > > > unlist(sample.size) > > > > Duncan Murdoch > > > > > btw, as to classification problem for this with uneven > class number > > > situation, do u have some suggestions to improve its accuracy? I > > > tried to use c() way to make the sampsz works but the result is > > > similar. > > > > > > Thanks, > > > > > > weiwei > > > > > > On 6/30/05, Liaw, Andy <[EMAIL PROTECTED]> wrote: > > >> The limitation comes from the way categorical splits are > represented in the > > >> code: For a categorical variable with k categories, the split is > > >> represented by k binary digits: 0=right, 1=left. So it > takes k bits to > > >> store each split on k categories. To save storage, this > is `packed' into a > > >> 4-byte integer (32-bit), thus the limit of 32 categories. > > >> > > >> The current Fortran code (version 5.x) by Breiman and > Cutler gets around > > >> this limitation by storing the split in an integer > array. While this lifts > > >> the 32-category limit, it takes much more memory to > store the splits. I'm > > >> still trying to figure out a more memory efficient way > of storing the splits > > >> without imposing the 32-category limit. If anyone has > suggestions, I'm all > > >> ears. > > >> > > >> Best, > > >> Andy > > >> > > >> > From: [EMAIL PROTECTED] > > >> > > > >> > Hello, > > >> > > > >> > I'm using the random forest package. One of my factors in the > > >> > data set contains 41 levels (I can't code this as a numeric > > >> > value - in terms of linear models this would be a random > > >> > factor). The randomForest call comes back with an error > > >> > telling me that the limit is 32 categories. > > >> > > > >> > Is there any reason for this particular limit? Maybe it's > > >> > possible to recompile the module with a different cutoff? > > >> > > > >> > thanks a lot for your help, > > >> > kind regards, > > >> > > > >> > > > >> > Arne > > >> > > > >> > ______________________________________________ > > >> > [email protected] mailing list > > >> > https://stat.ethz.ch/mailman/listinfo/r-help > > >> > PLEASE do read the posting guide! > > >> > http://www.R-project.org/posting-guide.html > > >> > > > >> > > > >> > > > >> > > >> ______________________________________________ > > >> [email protected] mailing list > > >> https://stat.ethz.ch/mailman/listinfo/r-help > > >> PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > >> > > > > > > > > > > > > > > -- > Weiwei Shi, Ph.D > > "Did you always know?" > "No, I did not. But I believed..." > ---Matrix III > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
