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Dear All, The function curve() draws the graph of functions from R to R. Is there some homologous function to curve() to draw functions from R^2 to R? Thanks in advance, Paul

I want to generate a valid variance-covariance matrix. One way could be to generate some random sample from multivariate normal distribution and then calculate cov. matrix. Another way could be to sample from wishart distribution itself. However both cases need a valid i.e. PD covariance matrix. As I need to generate that covariance matrix only, I am not interested those two methods. Can anyone

Well, this is what i got... > -0.0841219200008394^(1/3) [1] -0.438163696867656 > (-0.0841219200008394)^(1/3) [1] NaN and i don't have a clue of why this happens or how to avoid it, any suggestions? thank you, Juan

Hi R-helpers, I have two queries relating to generalising to n dimensions: What I want to do in the first one is generalise the following statement: expand<-expand.grid(1:x[1],1:x[2],...1:x[n]) where x is a vector of integers and expand.grid gives every combination of the set of numbers, so for example, expand.grid(1:2, 1:3) takes 1,2 and 1,2,3 and gives 1,1 2,1 1,2 2,2 1,3 2,3 My x

Dear Listers, I've been a big fan of R since graduate school. After working in the industry for years, I haven't had many opportunities to use R and am mainly using SAS. However, I am still forcing myself really hard to stay close to R by reading R-help and books and writing R code by myself for fun. But by and by, I start realizing I have hard time to keep up with R and am afraid that I

...give it up. Is there any >>> idea how >>> I might keep touch with R without using it in work on daily basis? I >>> really >>> appreciate it. >>> -- Robin K. S. Hankin Senior Research Associate Cambridge Centre for Climate Change Mitigation Research (4CMR) Faculty of Economics The University of Cambridge rksh1@cam.ac.uk 01223-764877 ------------------------------ Message: 61 Date: Mon, 22 Sep 2008 09:30:52 +0100 (BST) From: (Ted Harding) <Ted.Harding@manchester.ac.uk> Subject: Re: [R] Why isn't R recognising integers as numbers? To: Te...