Re: [R] odesolve/lsoda differences on Windows and Mac UPDATE

From: Martin Henry H. Stevens <HStevens_at_MUOhio.edu>
Date: Thu 28 Jul 2005 - 23:51:30 EST

To all:
After talking to Woody Setzer offline, I ran my "problem" scripts again. I am embarrassed to say that it worked fine for all previously intransigent parameter sets. I compared the results to those of my Windows buddy, and they are essentially identical, with the average absolute difference at each time point is 1.3e-06. I am planning to go back and try to understand what went wrong before. I never used hmin (mistakenly of course, instead of hmax) UNTIL a run with default lsoda argument values failed. Now the default values work! Thus the mistaken use of hmin isn't the entire answer.
Thank you for the time and interest, and I apologize for troubling you. I will get back to the list if I can ever repeat the problem or if I can figure out what I did wrong.

Best Regards,
Hank

On Jul 27, 2005, at 12:36 PM, Martin Henry H. Stevens wrote:

> Hi -
> I am getting different results when I run the numerical integrator
> function lsoda (odesolve package) on a Mac and a PC. I am trying to
> simulating a system of 10 ODE's with two exogenous pulsed inputs to the
> system, and have had reasonably good success with many model parameter
> sets. Under some parameter sets, however, the simulations fail on the
> Mac (see error message below). The same parameter sets, however, appear
> to run fine for our computational technician on his PC, generating
> apparently very reasonable data.
>
> Our tech is successfully running
> Dell Latitude D810, Windows XP Pro (Service Pack 2), 1Gb
> RAM. RGUI 2.1.1
>
> I am running:
> R Version 2.1.1 (2005-06-20) on a
> Mac OS 10.3.9
> Machine Model: Power Mac G5
> CPU Type: PowerPC 970 (2.2)
> Number Of CPUs: 2
> CPU Speed: 2 GHz
> L2 Cache (per CPU): 512 KB
> Memory: 1.5 GB
> Bus Speed: 1 GHz
> Boot ROM Version: 5.0.7f0
> Serial Number: XB3472Q1NVS
>
> My Error Message
>> system.time(
> + outAc2 <- as.data.frame(lsoda(xstart,times, pondamph, parms,
> tcrit=170*730, hmin=.1))
> + )
> [1] 0.02 0.01 0.04 0.00 0.00
> Warning messages:
> 1: lsoda-- at t (=r1) and step size h (=r2), the
> 2: corrector convergence failed repeatedly
> 3: or with abs(h) = hmin
> 4: Returning early from lsoda. Results are accurate, as far as they go
>
> Thanks for any input.
>
> Hank Stevens
>
>
>
> Dr. Martin Henry H. Stevens, Assistant Professor
> 338 Pearson Hall
> Botany Department
> Miami University
> Oxford, OH 45056
>
> Office: (513) 529-4206
> Lab: (513) 529-4262
> FAX: (513) 529-4243
> http://www.cas.muohio.edu/botany/bot/henry.html
> http://www.muohio.edu/ecology/
> http://www.muohio.edu/botany/
> "E Pluribus Unum"
>
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>
Dr. Martin Henry H. Stevens, Assistant Professor 338 Pearson Hall
Botany Department
Miami University
Oxford, OH 45056

Office: (513) 529-4206
Lab: (513) 529-4262
FAX: (513) 529-4243

http://www.cas.muohio.edu/botany/bot/henry.html
http://www.muohio.edu/ecology/
http://www.muohio.edu/botany/

"E Pluribus Unum"

R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 29 00:10:25 2005

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