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I think one needs an LU decomposition rather than QR. However, I couldn't find anything off the shelf to do an LU, other than learning that determinant() now uses LU instead of QR or SVD, so the code to do it must be in there for those that want it. You'll probably need to divide rows of U by the first entry if you insist on the unique reduced REF. However, I can't see any reason

I was looking for an R-package that would reduce matrices to row-echelon form, but Google was not my friend; any leads? If not, I wonder if the problem could be expressed in terms of constraint satisfaction...

Hi everyone, I am looking to use R as a MATLAB replacement for linear algebra. I've done a fairly good job for finding replacements for most of the functions I'm interested in, I John Fox wrote a program for implementing the reduced row echelon form of a matrix (by doing the Gauss-Jordan elimination). I modified it a bit: rref <- function(A,

I don't normally have to go anywhere near this stuff , but it seems to me that this should be a straight-forward process in R. For the purposes of this enquiry I thought I would use something I can work out on my own. So I have my matrix and the right hand results from that matrix tdata <- matrix(c(0,1,0,-1,-1,2,0,0,-5,-6,0,0,3,-5,-6,1,-1,-1,0,0),byrow = T,ncol = 5) sumtd <-

I have a data(ABC) like this: x y A 3 4 A 1 3 B 2 6 B 4 8 C 5 4 C 6 7 I want to split this data into A: x y A 3 4 A 1 3 B B 2 6 B 4 8 C C 5 4 C 6 7 anyone knows how to do that? thanks, Aimin Yan

I have a dataset like this: p aa index x y z sdx sdy sdz delta as ms cur sc 1 821p MET 1 -5.09688 32.8830 -5.857620 1.478200 1.73998 0.825778 13.7883 126.91 92.37 -0.1320180 111.0990 2 821p THR 2 -4.07357 28.6881 -4.838430 0.597674 1.37860 1.165780 13.7207 64.09 50.72 -0.0977129 98.5319 3 821p GLU 3 -5.86733 30.4759

I am trying to fit a logistic regression model for this data set. Firstly, I want to plot P(Y=1) vs As and P(Y=1) vs Aa. Does any body know how to do these in R. Thanks, Aimin > p5 <- read.csv("http://www.public.iastate.edu/~aiminy/data/p_5_2.csv") > str(p5) 'data.frame': 1030 obs. of 6 variables: $ P : Factor w/ 5 levels "821p","8ABP",..: 1

I have a question in R. In directory H:/Delta_angle I have 19 files like this: ALA.delta ASN.delta ASP.delta CYS.delta GLN.delta GLU.delta HIS.delta ILE.delta LEU.delta LYS.delta MET.delta PHE.delta PRO.delta SER.delta THR.delta TRP.delta TYR.delta VAL.delta I want to read these files to 19 data sets in R. All these data sets have "P","AA",index","delta"

Hello, I use nnet to do prediction for a continuous variable. after that, I calculate correlation coefficient between predicted value and real observation. I run my code(see following) several time, but I get different correlation coefficient each time. Anyone know why? In addition, How to calculate prediction accuracy for prediction of continuous variable? Aimin thanks, > m.nn.omega

I try Sweave and get Sweave-test-1.tex but hot to run LaTeX on 'Sweave-test-1.tex'? I am using WinEdt. thanks, Aimin > Sweave(testfile) Writing to file Sweave-test-1.tex Processing code chunks ... 1 : print term verbatim 2 : term hide 3 : echo print term verbatim 4 : term verbatim 5 : echo term verbatim 6 : echo term verbatim eps pdf 7 : echo term verbatim eps pdf

I have a data set like this I want to assign "outward" to Y if sc <90 and assign "inward" to Y if sc>=90. then cbind(p1982,Y) to get like these p aa as ms cur sc Y 1 154l_aa ARG 152.04 108.83 -0.1020140 92.10410 inward 2 154l_aa THR 15.86 28.32 0.2563560 103.67100 inward 3 154l_aa ASP 65.13 59.16 0.0312137 7.27311 outward 4 154l_aa CYS 57.20 49.85

Dear R list, I have a question in R, it could be very simple, but I don't know how to do it? for example: I assign 6 to x in beginning of of my R script code > x<-6 ...... After many line code, I forget using x variable before, I use x again, and do assignment like this > x<-45 > x [1] 45 then value 6 of previous x is replaced by 45. I am wondering if there are some way R

How to add mean,sd, number of observation in each panel for lattice histogram? Aimin

Does anyone know how to solve this question about R.matlab? I am in windowsXP, my matlab is matlab 7.0.0 19920(R14) thanks, Aimin > matlab <- Matlab(host="localhost", port=9998) > if (!open(matlab)) throw("Matlab server is not running: waited 30 seconds.") Error in list("throw("Matlab server is not running: waited 30 seconds.")" =

In order to start matlab server in R , I using the following commands getwd() setwd("D:\R_matlab") install.packages("R.oo") install.packages("R.matlab") install.packages("R.utils") library(R.matlab) Matlab$startServer() a minimized MATLAB Command Window come out, but I can't make this window become larger. Does anyone know why? I type

I have a set data={A,B,C,D,E,F,G} I want to choose 2 letter from 8 letters, i.e. generate the combination set for choose 2 letters from 8 letters. I want to get the liking: combination set={AB,AC,AD,....} Does anyone konw how to do in R. thanks, Aimin

Hi, all. I want to write some functions like glm() so i studied it. In glm.fit(), it calls a fortran subroutine named "dqrfit" to compute least squares solutions to the system x * b = y To learn how "dqrfit" works, I just follow how glm() calls "dqrfit" by my own example, my codes are given below: > qr <- >

I draw dotplot using the following code: sd.dotplot<-dotplot(data.47.nmr$om_sd ~ as.factor(data.47.nmr$position) |as.factor(data.47.nmr$pr), data = data.47.nmr,layout=c(1,1), xlab="Position", xlim=range(data.47.nmr$position),ylab="Sd", main="Changes of omega angle in different positions", scales = list(x = list(rot = 45))) However I get same xlim for each

if I want to put fig1plot to the left, figYPplot to the right figYAaplot on the bottom. How to modify the following cod to do these? \begin{figure}[H] \centering \begin{minipage}[t]{0.5\textwidth} \centering <<label=fig1plot,fig=TRUE,echo=FALSE>>= <<fig1plot>> @ %\caption{Caption 1} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \centering

I try to type this in my R-winEdt. but I got these. Do you know? Aimin > install.packages('http://rh-mirror.linux.iastate.edu/CRAN/bin/windows/contrib/2.4/plotrix_2.1-6.zip') Warning in download.packages(pkgs, destdir = tmpd, available = available, : no package 'http://rh-mirror.linux.iastate.edu/CRAN/bin/windows/contrib/2.4/plotrix_2.1-6.zip' at the