search for: dlsoda

Dear R-users, I'm running an MLE procedure where some ODEs are solved for each iteration in the maximization process. I use mle2 for the Maximum likelihood and deSolve for the ODEs. The problem is that somewhere along the way the ODE solver crashes and I get the following error message: DLSODA- Warning..Internal T (=R1) and H (=R2) are such that in the machine, T + H = T on the next step (H = step size). Solver will continue anyway. In above, R1 = 0.2630651367072D+01 R2 = 0.2055665829864D-15 .... Error in optim(par = par, fn = U, method = "Nelder-Mead", contro...

Hi All It has been suggested to me that the folks in this list might be able to help me out of my misery. As part of my learning curve to building a rather detailed model of a small neurone complex I am implementing some existing models in R. For the moment I want to implement the Izhikevich model as described in his 2003 paper. The equations are as follows: v' = 0.04v^2 + 5v + 140 - u - I

Hi All I have been struggling with this model for some time now and I just can't get it to work correctly. The messages I get when running the code is: DLSODA- Warning..Internal T (=R1) and H (=R2) are such that in the machine, T + H = T on the next step (H = step size). Solver will continue anyway. In above message, R = [1] 0 0 DINTDY- T (=R1) illegal In above message, R = [1] 0.1 T not in interval TCUR - HU (= R1) to TCUR (=R2) In ab...

...0.01, 5)) Z.int = P.int/7 N.int = c(rep(0.1, 13), rep(4.55, 5), rep(10,12)) state = c(P.int, Z.int, N.int) Time = seq(0,100, by = 1) NPZ.out <- ode.1D(state, Time, NPZ, params1, nspec = 3, names = c("P","Z","N")) After running for about 7 hours, the result returns: DLSODA- At current T (=R1), MXSTEP (=I1) steps taken on this call before reaching TOUT In above message, I = [1] 5000 In above message, R = [1] 0.0498949 Warning? 1: In lsoda(y[ii], times, func = bmod, parms = parms, bandup = nspec * : an excessive amount of work (> maxsteps ) was done, but i...

I have data that looks like this: > df1 group id 1 red A 2 red B 3 red C 4 blue D 5 blue E 6 blue F I want a list of the groups containing vectors with the ids. I am avoiding subset(), as it is only recommended for interactive use. Here's what I have so far: df1 <- data.frame(group=c("red", "red", "red", "blue",