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

[Martin Henry H. Stevens]

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"
>
> ______________________________________________
> R-help at 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
>
>
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"