similar to: specifying multiple parameter starting values in nlm

Hi, there I am a graduate student new to coding in S who is hitting a bit of a wall at present using an "optim" function. I am running into some troubles, and was hoping someone might be able to recognize where I am going wrong. As background: I have constructed a loop that carries out a 365-day calculation for a mass-balance model. Basically, the model depends on 2 variables (p,

Hi there I thought this would be of particular interest to people using 'optim' functions and perhaps people involved with R development. I've been beaten down by R trying to get it to perform an optimization on a mass-balance model. I've written the same program in excel, and using the 'solver' function, it comes up with an answer for my variables (p, ACT, which

Hi, there I am a grad student struggling to get my syntax right in a model I am building in R. I am trying to specify a variable,W, in a loop, such that on the first iteration, it is equal to Wo, my starting value, which I have already specified with Wo<-9.2 On any other iteration other than the first, I want W to equal the previous value of W in the iteration. plus an increment from

Hi there, I just wanted to take a quick second to thank everyone who maintains this service- just in case you don't hear it enough, there are a plethora of people who rely on this service (as evidenced by the help archives), and even if they don't say it, are greatly thankful for what you do here. Not only are you providing a service to people who are learning R, but indeed helping

Hi there, I've hit a bump in writing postscript files with special characters in the WinAnsi encoding on a windows machine. Here's some sample code: ########################################### postscript(file = "test.eps", encoding="WinAnsi.enc", width = 3, height = 5.5, onefile = TRUE, horizontal=FALSE, family = "sans", title =

Hi, there I am trying to replicate an error message in subset() to see what it is that I'm doing wrong with the datasets I am trying to work with. Essentially, I am trying to pass a string vector to subset() in order to select a specific collection of cases (i.e., I have data for these cases in one table, and want to select data from another table that match up with the cases in the

Hi there, I'm sure there's an easy answer to this, and I can't wait to see it. The question: is there an easy way to sort a data frame by it's row names? My dilemma: I've had to pull apart a data frame, run it through a loop to do some calculations and generate new variables, and then re-construct the chunks back into a data frame at the end. Doing this preserves the row

Hi, there I tried this post on R-help but did not generate any replies, so I thought I might try the waters here since it's a more programming-based group. I have written a function that will allow me to calculate the variance components for a model II (random effects) single factor ANOVA (perhaps this is me re-inventing the wheel, but I handn't yet come across anything in R that does

Hi, there I'm currently trying to figure out how to keep my "factor" levels for a variable when moving it from one data frame or matrix to another. Example below: vec1<-(rep("10",5)) vec2<-(rep("30",5)) vec3<-(rep("80",5)) vecs<-c(vec1, vec2, vec3) resp<-rnorm(2,15) dat<-as.data.frame(cbind(resp, vecs))

Hi there, Does anyone know how to extract elements from the table returned by Manova()? Using the univariate equivalent, Anova(), it's easy: a.an<-Anova(lm(y~x1*x2)) a.an$F This will return a vector of the F-values in order of the terms of the model. However, a similar application using Manova(): m.an<-Manova(lm(Y~x1~x2)) m.an$F Returns NULL. So does any attempt at calling the

Hi, all I have a rather un-ideal dataset that I am trying to work with, and would appreciate any advice you have on the matter. I have 4 years worth of data taken at 3 depth-zones from which samples have been taken at random. I am looking at the abundance of organism A between depth zones and across years, and am interested in the possible interaction of organism A distributions shifting

Hi all, Does anyone have any tips for extracting chunks of data from a distance matrix? For instance, if one was interested in only a subset of distance comparisons (i.e., that of rows 4 thru 6, and no others), is there a simple way to pull that data out? >From some playing around with an example (below), I've been able to figure out that a distance matrix in R is stored as a single

Hi, My question is how do I gain control over what values the X and Y axis show. Below is a sample plot I have made and want the X axis to represent a time vector with values taking the form Q1.60, Q2.60, Q3.60...Q1.90..etc...Currently the X axis starts with value 0 and increases by 1 through the end of the sample. win.graph() matplot(v.0,log.diff.v.6,type="l",lty=1, col=2,

Hi, there I have a loop that is producing data, but is also generating an error message that I can't understand. Here's the loop and the error message: > bio<-matrix(NA, ncol=9, nrow=366) > W<-NULL > M<- length(Day) #number of days iterated > > for (i in 1:M) + { + + + if (Day[i]==1) W[i] <- Wo else W[i] <- (W[i-1]+(Gr[i]/Ef)) + + + C<-

Hi, there I am quite sure there is an easy answer to this, but I am unsure how to gather a bunch of t-statistics in an organized format. I am trying to generate a list of t-statistics for a randomization routine. If I try to collect a bunch of t-statistics from a run, this is what happens: > M <- 10 ; simt <- NULL > for(i in 1:M) + { + perm<-sample(site,replace=F) + +

Hi there, Quick question about the output from the sem() function in the library of the same name. If I am getting probabilities >0.05 for some of my estimates of path coefficients, I'm assuming the interpretation here is that the coefficient is not significantly different from zero, correct? In that case, might it make sense that I should disregard path coefficients between

Hi, there I'm trying to get the value of the Mean Square from the ANOVA model summary that comes from specifying the error term, and am wondering if one can actually do this ( I know it's possible when using anova(lm) objects and the like, but I'm having a tough time with it under this framework). There does appear to be some indexing in the output of this type, but perhaps not

Hi, there I'm trying to plot what is returned from a call to tapply, and can't figure out how to do it. My guess is that it has something to do with the inclusion of row names when you ask for the values you're interested in, but if anyone has any ideas on how to get it to work, that would be stellar. Here's some example code: y1<-rnorm(40, 2) x1<-rep(1:2, each=20)

Dear List, I have examined the sp, maptools, and shapefiles packages (Windows) but cannot seem to figure out a solution for writing shapefiles for 'curvy shapes'. The scenario is that I generate a series of polygons, circles, and ellipses on a plot and would like to convert them to shapefiles. Since the circles and ellipses are do not return a coordinate list during the plotting

Hi, there I first sent this e-mail a couple months ago, to no avail.Since I am not a member on your mailing list, so could you please cc: a response to me? I'll be sure to check the list today for replies. I am currently attempting to perform an ANOVA with both nested and normal factors. My problem is that R is treating my nested factors the exact same way as it would interaction terms.