similar to: nonlinear equation solver?

Hi, Does somebody knows of the existence of a library of functions for solving differential equations, I need a solver for a system of non linear first order differential equations. I think there was something in IMSL but that was a long time ago and probably there are some new algorithms in the new now. Thanks for any pointers. . R. Heberto Ghezzo Ph.D. Meakins-Christie Labs McGill

[This message is not always serious, but it addresses a real problem.] A problem with R's present name is that it is not very well suited to search engines, although Google at least seems to cope as long as you have sufficient other terms to filter out Toys R Us. Initials remain a problem. I suppose "R" is just too culty to do away with, but perhaps we could come up with a longer

I am introducing the scan() function to my class. Consider the following file (Scanexamp.Rnw ) \documentclass[12pt]{article} \begin{document} <<>>= height = scan() 64 62 66 65 62 69 72 72 70 part = scan(what = character(0)) "Soprano" "Soprano" "Soprano" "Alto" "Alto" "Tenor" "Tenor" "Bass"

I found myself wanting to average a vector [vec] within each level of a factor [Fac], returning a vector of the same length as vec. After a while I realised that lm1 <- lm(vec ~ Fac) fitted(lm1) did what I want. But there must be another way to do this, and it would be good to be able to apply other functions than mean() in this way. Cheers, Murray -- Dr Murray Jorgensen

I am trying to fit a nonlinear regression model to data. There are several predictor variables and 8 parameters. I will write the model as Y ~ Yhat(theta1,...,theta8) OK, I can do this using nls() - but "only just" as there are not as many observations as might be desired. Now the problem is that we have a factor "Site" and I want to include a corresponding error

Dear all, Is there any generic algorithm code for optimization implemented in R? I searched without success. Thanks, -- Zhu Wang Statistical Science Department Southern Methodist University Phone: (214)768-2453 Fax: (214)768-4035 Email: zhuw at mail.smu.edu

How do you stop R from putting up a dialog box when you quit Rgui? (I use Windows and I never save workspaces that way) Murray -- Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html Department of Statistics, University of Waikato, Hamilton, New Zealand Email: maj at waikato.ac.nz Fax 7 838 4155 Phone +64 7 838 4773 wk +64 7 849 6486 home

I'm running R 1.2.2 under windows 98 on a Pentium 133 laptop. I can't seem to retrieve the package MASS data sets: > library(MASS) > data(wtloss) Warning message: Data set `wtloss' not found in: data(wtloss) > data(abbey) Warning message: Data set `abbey' not found in: data(abbey) And yet all the .rda files for the MASS datasets are in D:\Program

I'm going to try my hand at converting some Fortran programs to R. Does anyone know of any good articles giving hints at such tasks? I will post a selective summary of my gleanings. Cheers, Murray -- Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html Department of Statistics, University of Waikato, Hamilton, New Zealand Email: maj at waikato.ac.nz

I want to interlace two vectors. This I can do: > x <- 1:4 > z <- x+0.5 > as.vector(t(cbind(x,z))) [1] 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 but this seems rather inelegant. Any suggestions? Murray -- Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html Department of Statistics, University of Waikato, Hamilton, New Zealand Email: maj at waikato.ac.nz

Greetings all. Any help with the following would be appreciated. I want to create a data frame for each file in a directory. The following code does not work but it may show what I am trying to do: carmakes <- c('BMW','Chrysler','Citroen','Fiat','Ford','Holden','Honda',

I got a shock a few days ago when I accidentally visited www.r-project.com . I thought that the r-project site had been hacked until I realised my mistake. There is also a site www.r-project.net. Both of these sites appear to be Japanese. Does anyone know anything about them? I suppose that it is not unusual for names close to those of popular sites to be used. It is good that they use a

Has anyone got a cute way of compiling a table of the available plotting symbols? I've been repeatedly pasting in cno <- cno + 1 cno plot(x,y,pch=cno) which is tedious, and besides I have to note down the symbols by hand. Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html Department of Statistics, University of Waikato, Hamilton, New Zealand Email: maj at

I have the feeling that this is a dumb question but oh well ... When I have an object x with several attributes, y <- x will make a copy of x with all the attributes included. What if I just want y to get the value assigned but nothing else (no class, names, dim or other attributes)? Johann -- Phone/FAX/Adr/PGPkey ... at http://www.ai.univie.ac.at/~johann

I am exploring the result of clustering a large multivariate data set into a number of groups, represented, say, by a factor G. I wrote a function to see how categorical variables vary between groups: > ddisp <- function(dvar) { + csqt <- chisq.test(G,dvar) + print(csqt$statistic) + print(csqt$observed) + print(round(csqt$expected)) + round(csqt$residuals) + } > > x

Well I don't know if anyone can help with this but it will be interesting to know if others have had the same problem. I can't start R at home on my laptop [ I'm using 1.8.1 under Windows XP]. When I click on the shortcut I get the usual Windows box for when an application needs to close. A couple of clicks down it displays the following: Error signature AppName: rgui.exe

Hi, What is the best text editor for programming in R? I am using JEdit as the text editor, however, it does not have anything specific for R. It will be nice to have a developing environment where the keywords are highlighted, plus some other debugging functions. Yi-Xiong [[alternative HTML version deleted]]

Hai - kann mir jemand sagen, wie ich den Modalwert in R berechne?! IRgendwie finde ich den Befehl nicht.... greetz und herzlichen Dank Sonja

If I want to display a few polynomial regression fits I can do something like for (i in 1:6) { mod <- lm(y ~ poly(x,i)) print(summary(mod)) } Suppose that I don't want to over-write the fitted model objects, though. How do I create a list of blank fitted model objects for later use in a loop? Murray Jorgensen -- Dr Murray Jorgensen

Having just update to R 2.6.2 on my old Windows laptop I notice that the number of packages is growing exponentially and my usual approach of get-em-all may not be viable much longer. Has any thought been given to dividing "contributed" binaries into a recommended set, perhaps a couple of hundred, and the remained. That way one could install the recommended ones routinely and add in