similar to: how to do interpolation

Hi, I've got a matrix, Z, of values representing (as it happens) optical power at each pixel location. Since I know in advance I've got a single, convex peak, I would like to do a 2D parabolic fit of the form Z = poly((x+y),2) where x and y are the x,y coordinates of each pixel (or equivalently, the row, column numbers). Is there an R function that lets me easily implement that?

Hi, Suppose I have a multivariate response Y (n x k) obtained at a set of predictors X (n x p). I would like to perform a linear regression taking into consideration the covariance structure of Y within each unit - this would be represented by a specified matrix V (k x k), assumed to be the same across units. How do I use "lm" to do this? One approach that I was thinking of

Hello List! I asked this before (with no solution), but maybe this time... I'm trying to project a surface to the XY under a 3d cloud using lattice. I can project contour lines following the code for fig 13.7 in Deepayan Sarkar's "Lattice, Multivariate Data Visualization with R", but it fails when I try to "color them in" using panel.levelplot. ?utilities.3d says there

Hello: If anyone could guide me with this I would greatly appreciate it. Thanking you in advance for your assistance. Using a 3-level input factor alternative so that a function(below) can compute both a two-sided and one-sided p-values. Making the two-sided test the default. And produce output information about which alternative was tested. Where would I place the ifelse statement?

This was sent to me by someone on the R-list ( I don't know her ) but I don't have time to look at this right now so I told her I would send it to the R-list because she said it keeps getting bounced when she sends it. #======================================================================= ==================================================================== I am a bit confused with

Hello, Is there a simple way to make a plot with xy coordinates and a z value which determines the size and the color of point on the plot? Thanks for your help ! Emilie -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe"

Hello, does anyone know of a quick way to create a data frame "like" another, but with more rows? What I'd like to do is this: if mydata is a data.frame like a b c 1 TRUE yes 2 FALSE no 3 TRUE yes I'd like to get mydata2 with the same column names and column types, but without the values and with more rows. All I could think of was to manually do

Hi, I am a biologist (relatively new to R) analyzing data which we predict to fit a power function. I was wondering if anyone knew a way to model piecewise functions in R, where across a range of values (0-x) the data is modeled as a power function, and across another range (x-inf) it is a linear function. This would be predicted by one of our hypotheses, and we would like to find the AICs

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Symptoms: curve with log x axis gets the wrong x limits (in 2.6.1, I believe introduced in this version). Credit goes to Mike McCoy for detecting the problem. Demonstration: x = 1:5 plot(x,5*exp(-x),xlim=c(0.1,1000),log="x") xvec = 10^seq(-1,3,length=100) lines(xvec,5*exp(-xvec)) curve(5*exp(-x),add=TRUE,col=2,lwd=3) I believe

Hello, fellow Rdicts, I have the code for the program below. I need to integrate a function of "x" and "p". I use integrate to integrate over "x" and pass "p" as an additional argument. "p" is specified and given default value in the argument list. Still, integrate() cannot read "p", unless I explicitly insert a numeric value in the

Hi all, Running R 0.90.1 on a RH 6.1 system. Installation of the integrate_2.1-2 package went smoothly. My code contains a loop in which integrate() is called several times in each pass. I get a segmentation fault after what seems to be a random number of calls to integrate(). Debug output shows: Program received signal SIGSEGV, Segmentation fault. promiseArgs (el=0x40276414,

Hello, everybody I run the following program, and depending on the size of eps I get different results. With eps=1e-05, the program calculates wrong values for x=65:67 and others. The program runs fine with eps=1e-07. Why is this so? Also, I am using area() instead of integrate() because I cannot make integrate to work, especially with imaginary numbers. Maybe someone can show me how to use

Rd.sty defines \newlength{\middle} which seems to be in conflict with the my latex installation. Here is a minimal example: \documentclass{article} \newlength{\middle} \begin{document} \end{document} It runs fine on a Linux box: carp:136% latex test.tex This is TeX, Version 3.14159 (Web2C 7.3.1) (test.tex LaTeX2e <2000/06/01> Babel <v3.7h> and hyphenation patterns for american,

Dear R experts, I am plotting the population of students who live in a city, and in successive circular bands made of the contiguous districts that surround the city. This is a stylized figure, where I specify the area of each successive circle based on the cumulative population of students. I want to compare two sets of concentric circles across different populations - such as 'All

Hi everyone, newbee query! I've installed R 2.8.0 and tried to run this simple glm - x is no of cars in a given year, y is the number voted in an election that year while n is the population 18+: votes <- data.frame(x = c(0.62,0.77,0.71,0.74,0.77,0.86,1.13,1.44), + y=c(502,542,711,653,771,806,934,1123), n=

Hi, Maybe a bit off topic for this list, bt anyway. I have received several feature requests for DarkIce to support downsampling of the audio input before passing it to lame or ogg vorbis. For example the audio read from the soundcard would be 44.1kHz, and lame would get it at 22.05kHz. I figure two ways of doing this: 1. For lame, one can specify the input and the desired mp3 sampling rate,

I'm trying to do the following out of sample regression with autoregressive terms and additional x variables: y(t+1)=const+B(L)*y(t)+C(1)*x_1(t)...+C(K)*x_K(t) where: B(L) = lag polynom. for AR terms C(1..K) = are the coeffs. on K exogenous variables that have only 1 lag Question 1: ----------- Suppose I use arima to fit the model:

Hello, Novice programmer. I'm writing C source code and compiling it in as *.dll in the terminal by R CMD SHLIB foo.c. It works, I'm on a 64 bits windows system. I have the lastest R 2.15.0 and Rtools using the gcc 4.6.3 compiler. However, that was a hello world run, and I installed GSL for the 64 bit system for fast MCMC. The Rcpp package was easy to use, but I opted for a C with GSL

Hello, I tried this posted on the R devel subforum but no help so far. Maybe the wider net will be fruitful. Probably a pretty simple issue. The short story goes, I'm writing C source code and compiling it in as *.dll in the windows terminal by R CMD SHLIB foo.c. It works, I'm on a 64-bit system. I have the lastest R 2.15.0 and Rtools, and I am using the gcc 4.6.3 compiler. However,

Hi there everyone, I have the following model (this is naturally a simplified version just for showing my problem, in case you're wondering this is a translog cost function with the associated cost share equations): C ~ á + â1 log X + â2 log Y + ã1 log Z + ã2 log XX C1 ~ â1 + â2 log YY + ã1 log ZZ Then I have some restrictions on the coefficients, namely that the sum of â equal 1 and the