similar to: Problem with ode

Dear R Community, I am trying to optimize a water quality model that I am using. Based on conversations with others more familiar with what I am doing I plan to implement DEOptim to do this. The water quality model is interfaced through a GUI. I have the input file necessary to alter parameters and run the model as a text file. To do the optimization I have figured out the general procedure

Hello All, I'm struggling to solve this ODE using R, vdpol <- function (h, v, t) ( list(c ( -0.1*v/(pi*(2*10*h-h^2)), (v = (-0.1*v/(pi*(2*10*h-h^2))^2) + 2*9.81*h)) )) library(deSolve) yini <- (c(h = 20, v=0)) nonstiff <- ode(y = yini, func = vdpol, times= seq(0, 30, by =

Hello, I have a syntactic problem with ode. How do I specify vectors of equations in ordinary differential equation systems. (i.e. in my case I want to simulate an a priory undefined number of species that have different parameters but the same behaviour) I demonstrate this using the Lotka Volterra example. The code below does not work and I have not a good idea how to specify this right. ##

Hello, I propose two small changes to spec.pgram to get modest speedup when dealing with input (x) having multiple columns. With plot = FALSE, I commonly see ~10-20% speedup, for a two column input matrix and the speedup increases for more columns with a maximum close to 45%. In the function as it currently exists, only the upper right triangle of pgram is necessary and pgram is not returned by

Hello, I would like to evaluate the relationship between flows and phytoplankton abundance (or Chlorophyll a concentrations) using a changepoint analysis.? Specifically, I have two study questions: Study Question 1: Are there certain flow thresholds that result in spikes in phytoplankton abundance? Study Question 2: Are the duration of certain flows important for phytoplankton abundance (e.g.,

While using DTrace to track down a problem recently, we came across an unexpected restriction: the compiler will not permit different speculations to be committed in the same instance of a probe identifier. For instance, consider the following useless D script: #!/usr/sbin/dtrace -s #pragma D option nspec=2 BEGIN { spec1 = speculation(); spec2 = speculation(); } END {

I have used Sweave a lot the latest year, but never really used any long function calls. If I have code which look like this ------------------------------------------------------------- gof <- benthic.flux(ID="Gulf of Finland", meas.conc=conc, bw.conc=bw.conc, time=times,

Matteo, I fully agree with David: please read the posting guide. Anyway, the error message says it all: "the estimated variance of the individual effect is negative". See e.g. the "basic panel" chapter (10 or 11) in Wooldridge's "Econometric Analysis of XS and Panel Data" to understand why this may happen. Stata's behaviour is (as far as I remember) to

Hi all, quick question: is the optional command "width" effective in the geom_errorbarh() layer of ggplot? Cause I can't get it works on this graph http://www.4shared.com/file/116919103/93488d88/iso_2PrsH.html pdf(file = "iso_2PrsH.pdf", width = 7, height = 7) NC60.iso.graph<-ggplot( NC60.DATA ,aes(Ce,Qe)) + geom_point(col=MaCouleur1, size=4) +

Hello, I am currently trying to show the abundance of two species of zooplankton within the North Sea as pie chart bubble plots. I followed Werner Wernersen's advice in R help (http://finzi.psych.upenn.edu/R/Rhelp02a/archive/48644.html) and used Paul Murrell's paper "Integrating Grid Graphics Output with Base Graphics Output" (in R News) to try and do this (using the gridBase

Dear list, I've recently become interested in comparing the spectral estimates using the different methods ("pgram" and "ar") in the spectrum() function in the stats package. With many thanks to the authors of these complicated functions, I would like to point out what looks to me like a bit of an inconsistency -- but I would not be surprised if there is good reasoning

I am a physician examining an NHANES dataset available at the NCHS website: http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/demo_d.xpt http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/hdl_d.xpt http://www.cdc.gov/nchs/about/major/nhanes/nhanes2005-2006/tchol_d.xpt Thank you to the R authors and the foreign package authors in particular. Importing from the SAS export

Dear gracious R community, I would like to produce charts of phytoplankton biomass changes through time. Each species has a line, and the biomass varies in mirror form along the line for each species along the X time axis. Here is an example of what I'd like to do: http://www.er.uqam.ca/nobel/r30240/Succession.jpg Any suggestions? Thanks David Bird UQAM, Montreal

Hi, Dummy data script and scripts are attached below. I would like to change the plot to look like this:

Hi everyone. I have a long label that I would like to split. I found that I could use "strwrap" for simple text. However, this is not working with this label: str = expression(paste("< 20 ?m phytoplankton ","(cells ? ",mL^-1,")")) plot(...., ylab = strwrap(str,20),...) I suspect this is because I'm using "expression" for form my label.

Hi all, I'd like to use superscript or subscript in the axis label of a graph. Is that possible in R? For instance in xlab="Ce (mmol/m3)", I'd need the "3" of cubic meter in superscript. Regards/Cordialement ------------- Benoit Boulinguiez Ph.D Ecole de Chimie de Rennes (ENSCR) Bureau 1.20 Equipe CIP UMR CNRS 6226 "Sciences Chimiques de Rennes" Campus

All, I've been using "sub" (subtitle) instead of "main" such that captions are below figures produced by xyplot. This works fine and captions are on a single line. However, when I try this for bar plots with error bars (altering the error.bars function form Crawley's The R Book, see below), the captions are split on more than 1 line. Is there a way to get the

DeaR R-fellows, I got a lot of help from you concerning the generation of heat maps, so I was able to write and work with a script for this purpose at last. Some visitors of our Ecological Station asked about the generation of the graphs and so I decided to write down a small description. Is it adviseable to publish the link to the article in an R-wiki (which?) so I can give back a little to the

Hi All, I have been trying to get to plot my PCA legend outside of the PCA plot, but success still alludes me. Can you guys please advise how I can achieve this. I used locater() to obtain coordinates for below the Comp.1 axis. Using these coordinates the legend disappears. Below is the code for the PCA and legend. Thanks in advance for the help. Regards Tinus r.cols <-

Dear R-help, In my Master thesis I measured 10 variables from 18 lakes. These measurements were taken 4 times a year in 3 depths, so I have 12 samples from each lake. I know that 12 samples can not be treated as replications, since they don't correspond to the same environmental characteristics and are not statistically independent, but I want to use these 12 samples as an estimate of an