similar to: Multivariate regression

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?

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 R Users, How to make a variable equidistance with time i.e. how to interpolate a variable if it is not sampled at equal time interval. Many thanks, Regards, Yogesh [[alternative HTML version deleted]]

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,

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

-----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, 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

r-devel list, I have recently written an R package that solves a linear least squares problem, and computes the multivariate normal density function. The bulk of the code is written in C, with interfacing code to the BLAS and Lapack libraries. The motivation here is speed. I ran into a problem computing the determinant of a symmetric matrix in packed storage. Apparently, there are no explicit

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

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:

Assume that we collect below data : - subjects = 20 males + 20 females, every single individual is independence, and difference events = 1, 2, 3... n covariates = 4 blood types A, B, AB, O http://r.789695.n4.nabble.com/file/n4245397/CodeCogsEqn.jpeg ?m = hazards rates for male ?n = hazards rates for female Wm = Wn x ?, frailty for males, where ? is the edge ratio of male compare to female Wn =

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"

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

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

Hi, I installed the package Hmisc with the command install.packages("Hmisc") without errors. When I try to load the library with command library(Hmisc) I get the error > library(Hmisc) Error in library(Hmisc) : there is no package called 'Hmisc' > version _ platform i386-pc-linux-gnu arch i386 os linux-gnu system i386,

I want to maximize a conditional likelihood function that is basically logistic conditional on the number of successes within strata. What would be a good starting place for this? A complication is that the denominator includes a term that is the sum over all permutations. Although there is no time dimension to the problem, it's possible a degenerate use of the Cox proportional hazards

Dear all, I tried to use "step" function to do model selection, but I got an error massage. What I don't understand is that data as data.frame worked well for my other programs, how come I cannot make it run this time. Could you please tell me how I can fix it? ***************************************************************************************************

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,