similar to: sub set selection

R-packages leaps and subselect implement various methods of selecting best or good subsets of predictor variables for linear regression models, but they do not seem to be applicable to logistic regression models. Does anyone know of software for finding good subsets of predictor variables for linear regression models? Thanks. -Ben p.s., The leaps package references "Subset Selection

hi all how does one simulate a random walk process? i.e y(0)=0 y(t)=y(t-1)+ e(t) where e(t) is normal(0,1) say. Regards allan

a simple question how does one produce plots on two different graphics devices? / allan

hi all a simple question i want to run simulations in r. i however want the experiments to be repeated at a later time with exactly the same numbers by other users. can i set the random number seed for rnorm in some way? e.g. is there some arguement that goes with rnorm? please supply an example regards Allan

Hi all this is a silly question since i should know the answer. lm(y~x) perfroms linear regression with the intercept included. How do i estimate the equation without the intercept? cheers

Hi all I want to calculate certain lags of a time series and plot them simultaneously on a graph. can anyone help?

hello all i searched the archives and couldn't get a solution to the following question. i have the following function: F=function(z,v) { if (v==-.5) return(1) else return(2*v/z + 1/Recall(z,v-1)) } and while testing whether it works (ie F(z,v) is approx = besselK(z,1+v)/besselK(z,V). the recursion formula allows one to calculate besselK(z,1+v)/besselK(z,V) for large values of z )

hi all this is a stats question. when undertaking factor analysis should the variables included always be continiuos random variables? could one include categorical data? e.g some survey type data my gut feeling is that one should not include categorical type data since factor analysis is based on the eigenanalysis of the correlation matrix of a group of variables. The introduction of

Hello, I would appreciate *any* ideas on this problem. I'm the maintainer of a package ("subselect"), which on CRAN's Daily Package Checks is OK on all flavours of R, except r-devel Linux x86_64, where there is a "memory not mapped" segfault with the very first example that is tried out (output below). Additionally, a user with an AMD64 machine has just reported a

Hi, I downloaded the subselect package from CRAN and installed it in the system wide R library path. During installation the package compiled the fortran sources with no errors. However, when loading the library gives me an error: > library(subselect) Error in dyn.load(x, as.logical(local), as.logical(now)) : unable to load shared library

hi all i would like to use r and winbugs in order to undertake seemingly unrelated regression. i am using the R2WINBUGS library. i just simulated a simple example (sample size is 25) in order to get the correct code. i suspect that the problem is in my definition of the prior. it wants a multivariate node. the example could be extended by including more than 1 X variable in the system of

hello all sorry for the following "none" R related question. does anyone know of a reference to calculate the following identity: |I + ABC| where I is an identity matrix and A, B,C may not have to be square matrices? you help will be greatly appreciated. H. V. Henderson; S. R. Searle SIAM Review, Vol. 23, No. 1. (Jan., 1981), pp. 53-60. provides a result to

hi all i have a simple question: lets assume that i can enter a variable (a) equal to some value, say 100. obviously a could be any value. i would like to create a plot with a main heading as hi all "some writing" + a how would own create a string by combining a string with a numeric variable? hope the question is not too confusing. e.g. say a=5 then i want something like

hi all hopefully some one can help. assume that i imported the following data into R (say the data frame is called a) x1 x2 x3 1 NA 3 1 2 NA 1 2 3 3 NA 6 4 5 9 7 5 6 7 8 9 NA 7 9 How can i construct a new data frame that only contains those rows that does not contain the NA's? is these a quick way? ie x1 x2 x3 1 2 3 4 5 9 7 5 6 7 8 9 in this example we can simple use

hi all why does R do this: (-8)^(1/3)=NaN the answer should be : -2 a silly question but i kept on getting errors in some of my code due to this problem. i solve the problem as follows: say we want : (-a)^(1/3) then : sign(a)*(a^(1/3)) works but there has to be a simpler way of soing such a simple mathematical operation. thanking you / allan

hi all i have another probably simple question. I have three variables say x, y and z. x and y are quite large and z is relative small. how can one plot the three variables on the same graph with two separate axis? (one for x and y and the other for z) e.g. x<-c(101,110,150,167,120) y<-c(120,135,175,95,200) z<-c(0.001, 0.15, 0.6, 0.8, 1) regards Allan

Trying to install subselect v0.8 on Redhat 7.3 and R 1.8.1 fails (below). Any help is greatly appreciated. Xiao-Jun * Installing *source* package 'subselect' ... ** libs f2c < anneal.f > anneal.c anneal: Error on line 263: Declaration error for fica: adjustable dimension on non-argument Error on line 263: Declaration error for valp: adjustable dimension on non-argument Error

Hi all Another simple question. I would like to plot three graphs one the same plot with different colours. Say red, blue and black. Here are the functions. r1<-1+5*cos(2*pi*seq(1:100)/20)+rnorm(100) r2<-1+7*sin(2*pi*seq(1:100)/20)+rnorm(100) r3<-1+7*sin(2*pi*seq(1:100)/20)+5*cos(2*pi*seq(1:100)/20)+rnorm(100) Regards Allan

how does one numerically intergate the following: A=function(x,y) { xy } over the range: 2<x<0 4<y<10 say. ie how would one set up the integrate function? i forgot!

======================================================================= Simple CRAN packages which do not compile without modifications (all others do) ======================================================================= -- akima /usr/bin/ld: multiple definitions of symbol _idlc_ -- fracdiff /usr/bin/ld: multiple definitions of symbol _gammfd_ (and others) -- odesolve --