similar to: Powell's unconstrained derivative-free nonlinear least squares routine, VA05AD

Good evening! I have a multi-dimensional minimization problem whose gradient is pretty hard to code. I tried Nelder and Mead method implemented in function optim and it does not work well. I also tried the quasi Newton method in optim using difference as approximate derivative. It does not work well either. I just went through Numerical Recipes book. The book discusses another method without

Folks, Has anyone implemented Powell's Method for minimisation in R ? Many thanks, Tolga

Hopefully an easy question. When drawing a rectangles in a lattice plot key, how do you omit the black borders? Here is an example adapted from one on the xyplot help page: bar.cols <- c("red", "blue") key.list <- list( space="top", rectangles=list(col=bar.cols), text=list(c("foo", "bar")) ) barchart( yield ~ variety | site,

Dear all, I'm analysing a survey, and creating a barchart of the different responses for each question. The questions are grouped according to a number of categories, so I'm using lattice to create a plot with each question in a category on it. The problem is that the response set for different questions within the same category varies. I want to be able to draw only the relevant

Is it possible to save plots as byte streams? For example, if I want the bytes for a PNG plot, I could use #Write the plot to a PNG file png("test.png") plot(1:10) dev.off() #Read the bytes back in from the file plotbytes <- readBin("test.png", "raw", n=2000) Ideally, I'd like to avoid having to bother writing to the file in the first place, and simply

Apologies if this isn't acceptable for the general help list. I'm running OpenBUGS model via the R2WinBUGS package interface, under Windows. Is it possible to terminate running models, short of using the Windows Task Manager to forcibly exit the program? Regards, Richie. Mathematical Sciences Unit HSL ------------------------------------------------------------------------

I'm trying to set up a lattice plot with two y-axes for each panel. (Yes, I know that multiple y-axes are generally a bad idea; the graph is for someone else and they want it that way.) I've used a custom yscale.component in xyplot to achieve this: myyscale.component <- function(...) { ans <- yscale.components.default(...) ans$right <- ans$left foo <-

I'm trying to find a way to change the font size in a mosaic plot (the grid version, not the base graphics one). Here's an example to demonstrate: #Basic plot library(vcd) mosaic(HairEyeColor, shade = TRUE) #Bad first guess: this stops the default cell colouring, and doesn't change the font size mosaic(HairEyeColor, shade = TRUE, gp=gpar(fontsize=16)) #This successfully changes

One tiny thing that would be very nice to have is a default value of n=1 in the random number generator functions, enabling, e.g., runif() instead of runif(1). This won't break anyone's existing code and ought to be relatively straightforward to do. Is there anyone in the core team who would be willing to include this change? ----- Regards, Richie. Mathematical Sciences Unit HSL --

Hello, I have to do an ANOVA (or is it a MANOVA) with 6 Variables (called HsL, LsH, Hp, Lp, G, and) and 6 categories (OQ, Go, RC, AV, CC, Sk), the examples in the literature couldn't help me so far. Who can help me?? Thank Britta

How do you persuade lattice to draw tick marks on both the left and right side of the y-axis, when relation="free" in the scales component? #Ticks appear on both sides histogram(~height|voice.part, data=singer) ##Ticks only on left histogram(~height|voice.part, data=singer, scales=list(y=list(relation="free"))) Providing tck as a vector of length 2 doesn't seem to

I'm presumably missing something very obvious, but how does one use the key.opts argument in labcurve (via Ecdf)? In this example, I want the key to be big and have a blue background, but it isn't and doesn't. ch <- rnorm(1000, 200, 40) sex <- factor(sample(c('female','male'), 1000, TRUE)) Ecdf(~ch, group=sex, label.curves=list(keys=c("f",

I've just found some behaviour which strikes me as odd, but I'm not sure whether it's a bug or a feature. If you don't mind, I'd like to explain via a couple of examples. Let x = 1:10. Then intuitively, to me at least, the command x[-integer(0)] should leave x untouched. However the actual output under R2.4.0 is integer(0). A slightly more involved example demonstrates

Using the maptools function "map2poly" I have created a map/polylist object - a map of the Great Lakes. My goal is to passively plot additional data on this map. Unfortunately I am not able to change (distort) the relative scale of the axes for the map, and so the sample points do not line up correctly on the map. In the code below, notice that I have set the same axis ranges on each

> In a lattice plot like this: > > win.graph() > xyplot(tmx~frequ|as.factor(as.numeric(spf)),groups=as.factor(blm), > data=tmx,type="l",pch=16,xlab="frequency (N)",ylab="Area held (ha)", > auto.key=list(blm,points=F,lines=T,title="Blm factor",cex.title=0.7, > cex=0.7,corner=c(1,1)),main="Mangroves target=1573ha",layout=c(2,3))

> I have a vector: > > q1<-c(4660,5621,5629,8030,8080,8180,8501,8190,8370,8200) > > The following command gives me the mean of its elements: > > mean(q1) > [1] 7346.1 > > What can I do to do the same for the variable 'height', but only for the > cases/rows which have one of the elements of q1 as 'number': > > number height > 1

I am using R2.9.0 under Windows XP SP 2 (32-bit). I just discovered a rather excellent programming font (http://www.dafont.com/bitstream-vera-mono.font). Since it isn't one of the fonts listed as an option in the RGui Configuration Editor, I manually editted my RConsole file font line to font = Bitstream Vera Sans Mono When I opened R, the text in the console displayed correctly, but

> I am trying to debug a program, and I think tryCatch will help. The > functions involved > process through so many times before I encounter the error, things > are a bit slow to > use debug and browser(). > > I've read the help file and postings on conditions, and am still > having trouble. > > While running my program I am getting a NAN from a called

Greetings, I'm working on image classification and for that I want to use the spectral slope as a feature for my classifier. For this I would prefer to calculate this feature using R, so far I've read my image and converted it's RGB representation into HSL. The spectral slope is computed over the Luminance component, so at the moment what I have is a NxN matrix of Luminance values.

The (*windows only*) xlsReadWrite package has been updated and the new version is available on CRAN. xlsReadWrite natively reads and writes Excel files (v97 - 2003). o Changes from v1.1.1 to v1.3.3 (versions between never really published) - ROWNAMES-support also for matrices (not only for data.frame) - explicit rowNames argument in interface. (stimulated by email Adrian Dusa) -