similar to: Inverse function

Dear All, My question is simple but I need someone to help me out. Suppose I have a positive definite matrix A. The funtion chol() gives matrix L, such that A = L'L. The inverse of A, say A.inv, is also positive definite and can be factorized as A.inv = M'M. Then A = inverse of (A.inv) = inverse of (M'M) = (inverse of M) %*% (inverse of M)' = ((inverse of

Also, it is possible to change "ylim" also? 2012/7/1 li li <hannah.hlx@gmail.com> > Dear all, > I have a few questions regarding the boxplot output from the > "geom_boxplot" function. > Attached is the output I get. Below are my questions: > > 1. How can I define the xlab and ylab myself? > Also I would like to remove

Dear all, For two sets of random variables, say, x <- rnorm(1000, 10, 10) and y <- rnorm(1000. 3, 20). Is there any way to overlay the histograms (and density curves) of x and y on the plot of y vs. x? The histogram of x is on the x axis and that of y is on the y axis. The density curve here is to approximate the shape of the distribution and does not have to have area 1. Thank you

Dear all, Y, X are bivariate normal with all the parameters known. I would like to generate numbers from the distribution Y | X > c where c is a constant. Does there exist an R function generating random numbers from such a distribution? Thank you very much. hannah [[alternative HTML version deleted]]

Hi all, I am trying to download the Rcolorbrewer package from Cran http://cran.r-project.org/web/packages/RColorBrewer//index.html It seems the files have been removed. Does anyone know where can I download the package? Thanks. Hannah [[alternative HTML version deleted]]

Hi all, I want to add 6 plots in the format of 2 columns and 3 rows as one figure in latex. The plots are in .eps file. I know how to add 2 plots side by side, but could not figure out how to do multiple rows. I know this may not be the right place to ask such a question. But I do not know who to ask, so just try my luck here. Thank you in advance.

Hi all, I have a function rho.f which gives a list of estimators. I have the following problems. rho.f(0.3) gives me the right answer. However, if I use rho.f(corr[4]) give me a different answer, even though corr[4]==0.3. This prevents me from using a for loop. Can someone give me some help? Thank you very much in advance. Hannah >

Dear all, I have the following problem with the uniroot function. I want to find roots for the fucntion "Fp2" which is defined as below. Fz <- function(z){0.8*pnorm(z)+p1*pnorm(z-u1)+(0.2-p1)*pnorm(z-u2)} Fp <- function(t){(1-Fz(abs(qnorm(1-(t/2)))))+(Fz(-abs(qnorm(1-(t/2)))))} Fp2 <- function(t) {Fp(t)-0.8*t/alpha} th <- uniroot(Fp2, lower =0, upper =1,

Hi all, I want to extract every 20th row of a big matrix, say 10000 by 1000. What is the simper way to do this? Thank you very much! Hannah [[alternative HTML version deleted]]

Dear all, I want to import just part of an excel data file into R. I would like to have the data imported without rownames or colume names. I used read.delim("clipboard", header=F). Somehow even though I added the argument "header=F", I still have the row names V1, V2, ..., Does anyone know how to fix this? Thanks very much in advance. Hannah [[alternative

Dear all, I need some help on plotting multiple boxplots on one figure. I have three matrix A, B and C. Each of them is a 1000 by 10 matrix. The 10 columns of all three matrix correspond to the 10 values of the same parameter, say k=1, ..., 10. I want to make a plot where x axis represents different values of k. For each k value, I want to plot three boxplots, one on top of another. For

Dear all, This may not be the right place for latex questions, but I do not know where else to ask the question. I have two subfigures. I want the first subfigure to have a caption on the side of it and the second subfigure to have a caption below it. Thank you. Hannah [[alternative HTML version deleted]]

Dear all, I have a question regarding changing the xlim and ylim in the function image(). For example, in the following code, how can I have a heatmap with xlim=ylim=c(0, 100) instead of (0,1). Thank you very much. x <- matrix(rnorm(10000, 0,1), 100, 100) image(x) Hannah [[alternative HTML version deleted]]

Dear all, Does any one know whether there is a help forum for sas? I know this is not relevant question to ask here but don't know where else to ask. Thank you. Hannah [[alternative HTML version deleted]]

Hi all, I have the following two function f1 and f2. f1 <- function(lambda,z,p1){ lambda*(p1*exp(-3*z-9/2)+(0.2-p1)*exp(4*z-8))-(1-lambda)*0.8} f2 <- function(p1,cl, cu){ 0.8*(pnorm(cl)+(1-pnorm(cu)))/(0.8*(pnorm(cl)+(1-pnorm(cu)))+p1*(pnorm(cl+3)+(1-pnorm(cu+3)))+(0.2-p1)*(pnorm(cl-4)+(1-pnorm(cu-4))))}-0.05 First fix p1 to be 0.15. (i) choose a lambda value, say lamda=0.6, (ii)

Hi all, I have a question regarding the density function which gives the kernel density estimator. I want to decide the bandwidth when using gaussian kernel, given a set of observations. I am not familiar with different methods for bandwidth determination. Below are the different ways in R on deciding the bandwidth. Can anyone give an idea on which ones are preferred. Also, how can I take

Dear all, In my R plot, I would like to add the title as "Estimator vs. Eta", where I want to use the greek letter eta. I was trying to use expression(plain("Estimator vs.") *eta* ). It does not seem to work. Can anyone familiar with this give some help? Thank you very much. Hannah [[alternative HTML version deleted]]

Hi all, I am have some difficulty with the legend function. I need to add a legend to describe the different line types in a plot. The legend box is small. It did not include sufficient length of each line type to help distinguish the differnt line types. Is there a way to fix this. Thank you Hannah [[alternative HTML version deleted]]

Hi all, I have some trouble reading data from a csv file. I used command "read.delim("clipboard") to read in the data. > aalpha.data <- read.delim("clipboard") > class(aalpha.data) [1] "data.frame" > dim(aalpha.data) [1] 8 25 > colnames(aalpha.data) [1] "X" "V1" "V2" "V3" "V4"

Dear all, I have the following program for a multiple comparison procedure. There are two functions for the two steps. First step is to calculate the critical values, while the second step is the actual procedure [see below: program with two functions]. This work fine. However, However I want to put them into one function for the convenience of later use [see below: program with one