commons-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Luc Maisonobe (JIRA)" <>
Subject [jira] [Created] (MATH-604) optional dense output in ODE step handlers leads to weird results
Date Sun, 26 Jun 2011 15:07:47 GMT
optional dense output in ODE step handlers leads to weird results

                 Key: MATH-604
             Project: Commons Math
          Issue Type: Bug
    Affects Versions: 2.2
            Reporter: Luc Maisonobe
            Assignee: Luc Maisonobe
             Fix For: 3.0

The requiresDenseOutput method defined in the StepHandler interface was first created as an
optimization feature to avoid calling computeDerivatives too many times for some integrators.
In fact, only Dormand-Prince 8 (5,3) needs it because we can save 3 calls per step when the
interpolator is not used.

This feature brings more problems than it solves:
* it forces users to implement this method despite its purpose is not clear,
* even if the method returns false, sometimes dense output will be generated (in fact when
there are events detectors),
* it creates problems with at least Gragg-Bulirsch-Stoer since this integrator really needs
* it will create the same problems for Adams integrators (they also need interpolation),
* this "optimization" is useful only for one integrator: Dormand-Prince 8 (5,3),
* in many cases, even for Dormand-Prince 8 (5,3) it does not optimize anything since people
will often need interpolation

So I would like to completely remove this.

Removing the method is backward compatible for users.

This message is automatically generated by JIRA.
For more information on JIRA, see:


View raw message