similar to: Minimizing the negative log likelihood function...

I would like to solve the following function in R: G <- function(k) (2*(1 - k)*(1 + 2*k)^.5)/(1+3*k) I want to be able to find "k" for a given "G" Thanks! Francois Aucoin [[alternative HTML version deleted]]

Hey, I was wondering if there existed a R function similar to 'fsolve' or 'fzero' Matlab functions? Thanks! Francois Aucoin [[alternative HTML version deleted]]

Dear all, I'm trying to process a log file which logs the date, the username and the computer number accessed. The table looks like this: >table.users          Date UserName Machine 1  2008-11-25     John     641 2  2008-11-25    Clive     611 3  2008-11-25   Jeremy     641 4  2008-11-25     Walt     722 5  2008-11-25     Tony     645 6  2008-11-26     Tony     645 7  2008-11-26    

Dear list members, I can't figure out how get 'xyplot' or 'dotplot' in the 'lattice' package to respect the 'lwd' value for specifying the border with for *symbols* (for lines it works fine). Example: ----- # Base graphics works fine (gives a 'fat? circle) plot(5, cex=10, pch=21, lwd=10) # But 'xyplot' or 'dotplot' doesn't

Hello everyone, I'm running the following for loop to generate random variables in chunks of 60 at a time (l), here h is of order in millions (could be 5 to 6 millions), note that generating all the variables at once could have an impact on the final results for(j in 1:h){ dat$t.o[seq(0,g1,l)[j]+1:l]<-dat$mu[seq(0,g1,l)[j]+1:l] + rnorm(l,0,dat$g.var[seq(0,g1,l)[j]+1:l]) } Is there any

I believe I have found a bug (or at least a misfeature) in plot.POSIXct. See the following example code. set.seed(1) x=seq(1,1e8,length=100)+round(runif(100)*1e8) y=as.POSIXct(x,origin="2001-01-01") plot(y) This plots some random (date)times against their indices. The y axis correctly shows appropriate values (years), but the x axis contains the single number '59:58' in the

Dear list members, I recall seeing a convenience function for applying multiple functions to one object (i.e., almost the opposite of 'mapply?) somewhere. Example: If the function was named ?fun? the output of fun(3.14, mode, typeof, class) would be identical to the output of c(mode(3.14), typeof(3.14), class(3.14)) Is my memory failing me, or does such a function already exists in a

Hi, The paper @ARTICLE{AlmironSilvaMM:2009, author = {Almiron, M. and Almeida, E. S. and Miranda, M.}, title = {The Reliability of Statistical Functions in Four Software Packages Freely used in Numerical Computation}, journal = {Brazilian Journal of Probability and Statistics}, year = {in press}, volume = {Special Issue on Statistical Image and Signal Processing}, url =

R version 2.7.0 RC (2008-04-20 r45403) When using semi-transparent filled plotting symbols, the border of the symbol has a different (darker) colour than the interior: plot(0, 0, pch=19, col="#FF000022") (Saving this as a PDF and looking at it magnified may make it easier to see.) This is pretty annoying, since when plotting partially overlapping points, the border colour dominates,

Dear All, I am struggling with extracting data from a data frame: x=data.frame(a=1:11,b=100:110) What I want is a list/vector in this sence: 1 100 2 101 3 102... For single rows, this works fine: as.matrix(x)[1,] For, say 2 rows, this works fine: z=c(as.matrix(x)[1,],as.matrix(x)[2,]) But z=c(as.matrix(x)[1:2,]) gives 1 2 100 101!? Is there an 'automated way' to produce a

A seemingly simple problem has me stumped. Is it possible to choose the number of colour breaks for a gradient scale in the current version of ggplot2? Here is a simple example: --------------------------------------------- x=-10:10 y=-10:10 dat=expand.grid(x=x,y=y) dat$z=dat$x^2+dat$y^2-100 ggplot(dat, mapping=aes(x=x, y=y, fill=z)) + geom_tile() + scale_fill_gradient2()

I have a dataset that contains numbers between -10 and 0. E.g. x = c(-9.23, -9.56, -1.40, ...) If I no do a > qplot(x, geom="histogram") I get the error: Error: position_stack requires non-overlapping x intervals Strangely, the following both work: > qplot(x * -1, geom="histogram") > qplot(x+100, geom="histogram") Has anyone else encountered this? Is this a

There are a number of functions that are dispatched to from split(). > methods('split') [1] split.data.frame split.Date split.default split.POSIXct Is there a way to figure out which of these variants is actually dispatched to when I call split? I know that if the argument is of the type data.frame, split.data.frame will be called? Is it the case that if the argument is not

Hi! Is it possible to have different axis limit for each facet in a ggplot2 plot? Here is an example: -------------------------------------------------------------- library(ggplot2) x=seq(-10,10,.1) y=cos(x) z=sin(x)*10 dat=melt(data.frame(x,y,z), id.var="x") qplot( x, value, data=dat, facets=variable~., geom="line" )

I'm having a problem where I have to apply a function to a subset of a variable, where the subset is defined by the n nearest neighbours of a second variable. Here's an example applied to the 'iris' dataset: $ head(iris) Sepal.Length Sepal.Width Petal.Length Petal.Width Species 1 5.1 3.5 1.4 0.2 setosa 2 4.9 3.0 1.4

Dear list members I'm using CairoPDF to generate PDF (because of its font embedding and support for transparent colours). However, at least on my (Windows) system, the text it outputs seems to have completely wrong kerning. Here's an example: CairoPDF("test.pdf") plot(rnorm(100),xlab="Ovreset") dev.off() The v is (slightly) too far away from the O, it's much

I want to include a vignette with a package I wrote. I did follow the "Writting R extentions" document step by step, but went I run "Rcmd build", an error occurs. It goes like this: " * creating vignettes ... ERROR . . . . :7: Emergency stop L7L ==> Fatal error occurred, no output PDF file produced!texify: pdflatex failed for some reason <see log file>.

Hi, I got the following problem. I am doing a maximum likelihood estimation for a Kalman Filter. For this purpose, I have to invert an error matrix Ffast of dimension "no. parameters X no.parameters". The usualy optim methods often find only local minima, so I decided to make the optimization using the SANN algorithm, which is very slow already. However, this becomes a real problem

I'm using the 'cloud' function in the 'lattice' package to produce multi-panel 3D scatter plots. The range of the values used vary much between each panel (especially on the z axis), so I wish the axis limits to be calculated based on the (conditional) data. Here's a minimal example: library(lattice) z=1:200 x=runif(200) y=runif(200) s=factor(rep(c(1,2),each=100))

When discussing statistics in e-mail based discussion groups, or in newsgroups, it is sometimes useful to include simple, text-based statistical graphics. Here is an example, a histogram (only useful with a fixed-width font, obviously). :..... ..:::::::::. .:::::::::::::::