Dear Karline Soetaert, I've just returned from a week of travel, so have not had a great deal of time to look at your request. From a brief rereading of the original lsoda documentation, it looks as if all I need to do is set a flag to a different value (jt to 4), and leave it up to the user to construct the function that calculates the jacobian properly. If you'd contact me directly, ideally with a test model, I will see if the modification is really that simple; if so, I'll make the change and release an updated odesolve to CRAN. Woody PS: Thanks, Martin
R. Woodrow Setzer, Jr. National Center for Computational Toxicology US Environmental Protection Agency Mail Drop B205-01/US EPA/RTP, NC 27711 Ph: (919) 541-0128 Fax: (919) 541-1194 Martin Maechler <[EMAIL PROTECTED] ath.ethz.ch> To "Soetaert, Karline" 11/14/2005 09:46 <[EMAIL PROTECTED]> AM cc R-help@stat.math.ethz.ch, Woodrow Setzer/RTP/USEPA/[EMAIL PROTECTED] Please respond Subject to Re: [R] odesolve with banded Martin Maechler Jacobian [was "no subject"] <[EMAIL PROTECTED] ath.ethz.ch> >>>>> "KSoet" == Soetaert, Karline <[EMAIL PROTECTED]> >>>>> on Mon, 14 Nov 2005 13:20:24 +0100 writes: KSoet> Hi, I am trying to solve a model that consists of KSoet> rather stiff ODEs in R. KSoet> I use the package ODEsolve (lsoda) to solve these KSoet> ODEs. KSoet> To speed up the integration, the jacobian is also KSoet> specified. KSoet> Basically, the model is a one-dimensional KSoet> advection-diffusion problem, and thus the jacobian is KSoet> a tridiagonal matrix. KSoet> The size of this jacobian is 100*100. KSoet> In the original package LSODA it is possible to KSoet> specify that the jacobian is banded, which makes its KSoet> inversion very efficient. KSoet> However, this feature seems to have been removed in KSoet> the R version. KSoet> Is there a way to overcome this limitation? Yes. But probably not a very easy one; maybe even a very cumbersome one... ;-) Note however that questions like these should typically be addressed at the package author - which you can always quickly find out via > packageDescription("odesolve") Package: odesolve Version: 0.5-12 Date: 2004/10/25 Title: Solvers for Ordinary Differential Equations Author: R. Woodrow Setzer <[EMAIL PROTECTED]> Maintainer: R. Woodrow Setzer <[EMAIL PROTECTED]> Depends: R (>= 1.4.0) Description: This package provides an interface for the ODE solver lsoda. ODEs are expressed as R functions or as compiled code. ....................... I've CC'ed this e-mail to Woodrow to help you for once <..........> KSoet> [[alternative HTML version deleted]] KSoet> ______________________________________________ KSoet> ......... KSoet> PLEASE do read the posting guide! KSoet> http://www.R-project.org/posting-guide.html if you do read that guide, it will tell you - why you should always use a 'Subject' for your e-mails - why HTML-ified e-mails are not much liked and what you can do about it. Regards, Martin Maechler, ETH Zurich ______________________________________________ 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