similar to: fast matrix-vector multiplication

Hi everyone, I am running this fixed effects model in R. The thing is, my own code and the canned routine keep returning different estimates for the fixed effects factors and intercept. (The other variables' estimates and R^2 are the same!!! weird!!) I attach my own code, just in case. I am pretty sure this would not have any fundamental error. Well, hopefully. I have been using this code

Hi all, I am trying to estimate a simple logit model. By using MLE, I am maximizing the log likelihood, with optim(). The thing is, each observation has different set of choice options, so I need a loop inside the objective function, which I think slows down the optimization process. The data is constructed so that each row represent the characteristics for one alternative, and CS is a

Hi, Is there any way to estimate a DEPENDENT variable through a GLM/LM model? Suppose I have the linear model: y=a0+a1*x1+a2*x2 (a0=1, a1=0.6, a2=0.8, x1~N(1,1), x2~N(0,1)). The alphas and the auxiliary variables are given and I have to estimate y. The point is if I estimate it, let¹s say algebraically, I get high variances that do not decrease as sample sizes increases... Is the any other way

Hi all, I am trying to figure out a way to improve my code's efficiency by avoiding the use of loop. I want to calculate a conditional mean(?) given time. For example, from the data below, I want to calculate sum((value|choice==1)/sum(value)) across time. Is there a way to do it without using a loop? time cum_time choice value 1 4 1 3 1 4

Hi, The "\preformatted" environment in Rd files doesn't seem to escape long sequences of backslashes properly when converted to pdf (LaTeX) documentation. I'm running R version 2.14 (from subversion, revision 57751) on Linux (RHEL). Here's an example from the command line: echo

R1.7.1/Win2k: Apologies if this posts twice - the first message was not in plain text. I have looked in help.start() and tried typing "crossprod" and "%*%" into the RGui to get an idea for what R is using as internal algorithms for its matrix computations/manipulations... to no avail. Could someone point me in the direction of some documentation? All I get for

Hi, Suppose I have an arbitrary function: arbfun<-function(x) {...} Is there a robust implementation of a numerical derivative routine in R which I can use to take it's derivative ? Something a bit more than simple division by delta of the difference of evaluating the function at x and x+delta... Perhaps there is a way to do this using D or deriv but I could not figure it out.

>>>>> peter dalgaard <pdalgd at gmail.com> >>>>> on Fri, 16 Sep 2016 13:33:11 +0200 writes: > On 16 Sep 2016, at 12:41 , Alexis Sarda <alexis.sarda at gmail.com> wrote: >> Hello, >> >> while testing the crossprod() function under Linux, I noticed the following: >> >> set.seed(883)

Hello, while testing the crossprod() function under Linux, I noticed the following: set.seed(883) x <- rnorm(100) x %*% x - sum(x^2) # equal to 1.421085e-14 Is this difference normal? It seems to be rather large for double precision. Regards, Alexis. [[alternative HTML version deleted]]

Hi, I have a data frame and want to merge adjacent rows if some condition is met. There's an obvious solution using a loop but it is prohibitively slow because my data frame is large. Is there an efficient canonical solution for that? > head(d) rt dur tid mood roi x 55 5523 200 4 subj 9 5 56 5523 52 4 subj 7 31 57 5523 209 4 subj 4 9 58 5523 188 4 subj 4 7

Hi all, I have been searching all sorts of documentation, reference cards, cheat sheets but can't find why R's crossprod(A, B) which is identical to A%*%B does not produce the same as Matlabs cross(A, B) Supposedly both calculate the cross product, and say so, or where do I go wrong? R is only doing sums in the crossprod however, as indicated by (z <- crossprod(1:4)) # = sum(1 +

Dear R-devel, Has anyone played with this? http://www.amd.com/us-en/Processors/DevelopWithAMD/0,,30_2252_2282,00.html <http://www.amd.com/us-en/Processors/DevelopWithAMD/0,,30_2252_2282,00.html> . I'll probably give it a shot... Best, Andy Andy Liaw, PhD Biometrics Research PO Box 2000, RY33-300 Merck Research Labs Rahway, NJ 07065 mailto:andy_liaw@merck.com

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Hello, I was trying to build some functions which I would like to integrate over an interval using the function 'integrate' from the 'stats' package. As an example, please consider the function h(u)=sin(pi*u) + sqrt(2)*sin(pi*2*u) + sqrt(3)*sin(pi*3*u) + 2*sin(pi*4*u) Two alternative ways to 'build' this function are as in f and g below: coeff<-sqrt(1:4)

Dear Wiz[R]ds, I am deeply grateful for the help from Duncan Murdoch, Gray Calhoun, and others. We are almost there. For whatever reason, I can't change the symbol from a circle to a triangle in the upright posture plots. Any ideas? I have included the problem in full. # tritiated (3H)-Norepinephrine(NE) disappearance from plasma # concentrations supine and upright # supine datasu <-

Y'all, I would like to have most of the variables in my function to be global instead of local. I have not found any references that tell me now to do that. If I have missed a reference please excuse me and tell me what I have missed. Thanks, Keith Jones

Hello everyone I am currently developing a web based R script editor. My idea is to pass the R script command as a string into the backend , then use the Rengine instance to parse the R script command and get the resutls. Do anyone know how to use Rengine instance to parse a R script String? if so, could you give me a small example (in Java)? i really appreciate. -- View this message in

Hi all! Do you know if there is any R function/package that can be used to estimate "logit" models with panel data and forecasting? Thanks, Moysés. -- Moysés Nascimento Bacharel em Estatística/UFES Mestre em Estatística Aplicada e Biometria/UFV Doutorando em Estatística e Experimentação Agropecuária/UFLA moysesnascim@gmail.com [[alternative HTML version deleted]]

I don't find a function to print a string to file. Would somebody let me know what function I should use?

Hi, I've just been browsing for IDEs for R, see e.g. http://www.linuxlinks.com/article/20080413133953606/R.html It's probably highly subjective, but which free IDE is the best one around? For the Python language, I've always been using IDLE. I like the syntax highlighting and the syntax suggestions the user gets while typing a function name. Ideally, the IDE should run on any