similar to: lsoda question from deSolve package

Dear Colleagues, Our group is also working on implementing the use of R for pharmacokinetic compartmental analysis. Perhaps I have missed something, but > fit <- nls(noisy ~ lsoda(xstart, time, one.compartment.model, c(K1=0.5, k2=0.5)), + data=C1.lsoda, + start=list(K1=0.3, k2=0.7), + trace=T + ) Error in eval(as.name(varName), data) : Object

Dear All wonder if you could provide some insights on the following: currently I have this code which produces the expected results: require(deSolve) pars <- list(k = 0.08,v=15) intimes <- c(0,0.5,12) input <- c(800,0,0) forc <- approxfun(intimes, input, method="constant", rule=2) derivs <- function(t, state, pars) { inp <- forc(t) dy1 <- - pars$k * state[1]

Hi, I was wondering why the results from lm and dynlm are not the same for what I think is the same model. I have just modified example 4.2 from the Pfaff book, please see below for the code and results. Can anyone tell my what I am doing wrongly? Many thanks, Werner set.seed(123456) e1 <- rnorm(100) e2 <- rnorm(100) y1 <- ts(cumsum(e1)) y2 <- ts(0.6*y1 + e2) lr.reg <- lm(y2

Dear All, I have a pair of .cpp and .def file can be compiled using VC++ and works perfectly well in S-PLUS. I wanted to do the same for R; so I followed the guidline given in "Building from a source-code library under Windows" as much as possible and manage to compile them using VC++ and call it from R. But it gives different answer from the one called from S-Plus. I know that I did

Dear All,   please help with some thoughts on overcoming the following issues, if possible:   #R Code   require(deSolve) require(FME) pars <- list(k = 0.06,v=18) intimes <- c(0,0.5,12,12.5,50) input   <- c(800,0,800,0,0) forc <- approxfun(intimes, input, method="constant") model <- function(pars, times=seq(0, 50, by = 1)) {   derivs <- function(t, state, pars) {     

Hi, I am doing a project on the simulation of glucose metabolism based on a pharmacokinetic modeling in which we have 4 differential equations. I did this in R by using the odesolve package. It works very well, but I have two questions: Here is the odemodel function _________________________________________________ Ogtt.Odemodel <- function(t, y, p) { absx <- c(-60, -45, -30,

I'm getting this error on the attached code and breaking my head but can't figure it out. Any help is much appreciated. Thanks, Vince CODE: library(deSolve) Res_DAE=function(t, y, dy, pars) { with(as.list(c(y, dy, pars)), { res1 = -dS -dES-k2*ES res2 = -dP + k2*ES eq1 = Eo-E -ES eq2 = So-S -ES -P return(list(c(res1, res2, eq1, eq2))) }) } pars <- c(Eo=0.02,

Vince, When that happens, one possible reason is that your DAE is of index > 1, which cannot be solved by daspk. The solver radau, also from deSolve can handle DAEs up to index 3, but you need to rewrite the problem in the form M*y' = f(x,y), where M is a mass matrix. If you do that for your problem, and solve it with radau, then radau complains that the "matrix is repeatedly

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. ##

Full_Name: Albrecht Gebhardt Version: 0.99.0 OS: alpha, osf4.0 Submission from: (NULL) (143.205.180.40) DEC cc doesn't like c++ style comments // like this one Please use standard cc comments or #if 0 ... #endif A quite large patch follows (I hope it will pass mailing with not too much wrapped lines): --- ./src/main/g_her_glyph.c.dec-cc.patch Mon Feb 7 14:48:10 2000 +++

disable bogus touchpad device model, which cause annoying dmesg on 2.6 kernel Signed-off-by: Edwin Zhai <edwin.zhai@intel.com> diff -r 7c951e3eb5ab -r 14d3890843d0 tools/ioemu/hw/pckbd.c --- a/tools/ioemu/hw/pckbd.c Wed Oct 19 11:53:00 2005 +0100 +++ b/tools/ioemu/hw/pckbd.c Thu Oct 20 18:28:18 2005 +0800 @@ -29,6 +29,9 @@ /* debug PC keyboard : only mouse */ //#define DEBUG_MOUSE +/*

As this forum proved to be very helpful, I got another question... I'd like to fit data points on which I have an error, dx and dy, on each x and y. What would be the common procedure to fit this data by a linear model taking into account uncertainty on each point? Would weighting each point by 1/sqrt(dx2+dy2) (and taking dx and dy as relative errors) in a lm() fit do the job? I would like to

Dear All I am trying to use svychisq with a two-dimensional table 4 x 5. The command I am using is summary(svytable(~dietperception+dietstatus,dudleyls1rake,na.rm=TRUE),"C hisq") It is throwing up an error message as follows: Error in NCOL(y) : only 0's may be mixed with negative subscripts In addition: Warning messages: 1: is.na() applied to non-(list or vector) in:

I need to solve a system of non-linear fourth-order differential equations. Is there a command which solves this system? Thanks in advance.

I have some output from a survey shown below and would like to insert total rows for each category to then be able to use it as a data set for further analysis. Is it possible to do this in R. In this example I would like to insert a row between rows 5 and 6, 10 and 11, 15 and 16, 20 and 21 and put in the sum of the rows 1-5, 6-10, 11-15, 16-20 and to delete row 21 which has NA in it. I would

Dear Professor Lumley I am relatively new to using R and also to logistic regression. We have analysed our Dudley Health Survey using the survey package. I am now trying to look at associations using svyglm but I am unsure of how to interpret the output and present the resulting model or whether there are any other things I should do to check the validity of the model. Below is an example of

Hi ! Has anyone connected to the Mass Pay API of PayPal using Rails ? I need to do this for a customer, and I wanted to know how easy/hard it was. I have no experience using SOAP, WSDL, etc. I saw soap4r[1] on the RAA[2]. This is probably what I''ll need to use. One question I haven''t answered yet is whether soap4r will accept PayPal''s certificates ? Thanks for any

Hello, I am an R newbie, trying to use lsoda to solve standard Lotka-Volterra competition equations. My question is: how do I pass a parameter that varies with time, like say, phix <- 0.7 + runif(tmax) in the example below. # defining function lotvol <- function(t,n,p){ x <- n[1]; y <- n[2] rx <- p["rx"]; ry <- p["ry"] Kx <-

Hi R used with C-code experts, I had a look at the archives and did not find anything on this, so hopefully I am not doubling up. I have previously used the following approach where I needed some very small/large numbers (using Brobdingnag): surfacewithdiff <- function(t, y, p) { const=p["const"] kay =p["kay"] psii=p["psii"]