Chronological Thread 

< Chronological >      < Thread >

---

> -----Original Message-----
> From: cellml-tools-developers-bounces at cellml.org [mailto:cellml-tools-
> developers-bounces at cellml.org] On Behalf Of Andrew Miller
> Sent: 28 July 2008 02:43
> To: cellml-tools-developers at cellml.org
> Subject: Re: [cellml-dev] r2499 - in CellML_DOM_API/trunk: CIS/sources
> interfaces
>
> CellML Automated Notifications wrote:
> > Author: jmar150
> > Date: 2008-07-28 12:43:07 +1200 (Mon, 28 Jul 2008)
> > New Revision: 2499
> >
> > Modified:
> > CellML_DOM_API/trunk/CIS/sources/CISImplementation.cxx
> > CellML_DOM_API/trunk/CIS/sources/CISImplementation.hxx
> > CellML_DOM_API/trunk/CIS/sources/CISSolve.cxx
> > CellML_DOM_API/trunk/interfaces/CIS.idl
> > Log:
> > First cut of solution to Tracker Item 31; this allows a tabulation
> step size to
> > be specified, and will produce results at those points. Note that the
> interface
> > to CIS was changed.
> >
>
> Hi all,
>
> One potential problem with the code as implemented (which I'm not yet
> entirely sure of the best way to fix) is that it is comparing floating
> point numbers for equality, which I believe will often not work out
> exactly with the numerical integrator codes due to finite precision,
> except in cases where the numbers can be represented exactly.

That's also my understanding (and experience).

> One option might be to allow time values which are within tolerance of
> the requested one through instead of a strict equality test.

That's one possible solution. Something else that I have been using
successfully in COR (but don't know whether it could be applied here, as I
am not familiar with the code) is to have something like:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
n = 1;
tStep = <whatever>;
tStop = n*tStep;
tEnd = <whatever>;

repeat
n++;

tStop = n*tStep;

<do_whatever>
until tStop == tEnd;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Otherwise, something that worries me is the fact that CISSolver.cxx contains
quite a bit of code that is duplicated. I have in
"CDA_CellMLIntegrationRun::SolveODEProblemGSL" and
"CDA_CellMLIntegrationRun::SolveODEProblemCVODE" in mind. This is very much
error prone and not neat at all.

Alan

---

• [cellml-dev] r2499 - in CellML_DOM_API/trunk: CIS/sources interfaces, Andrew Miller, 07/28/2008
  • [cellml-dev] r2499 - in CellML_DOM_API/trunk: CIS/sources interfaces, Alan Garny, 07/28/2008
    • [cellml-dev] r2499 - in CellML_DOM_API/trunk: CIS/sources interfaces, Andrew Miller, 07/28/2008
      • [cellml-dev] r2499 - in CellML_DOM_API/trunk: CIS/sources interfaces, Alan Garny, 07/28/2008

---

Archive powered by MHonArc 2.6.18.