[R] odesolve/lsoda differences on Windows and Mac

Martin Henry H. Stevens HStevens at MUOhio.edu
Wed Jul 27 18:36:17 CEST 2005

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
"E Pluribus Unum"

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