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Date: Thu, 04 Jun 2009 23:52:51 +0200
From: Luc Maisonobe <Luc.Maisonobe@free.fr>
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To: Commons Users List <user@commons.apache.org>
Subject: [math] Re: ODE Question
References: <23878418.post@talk.nabble.com>
In-Reply-To: <23878418.post@talk.nabble.com>
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Angelo Port a �crit :
> Hi,

Hello,

First, please use a marker like [math] when posting to this list
according to the commons component you use. This list is shared by
several components, so it helps subscribers filter the messages.

> 
>  
> 
> I am attempting to use the Dormand-Prince 54 integrator. I get the following
> error:
> 
> org.apache.commons.math.ode.IntegratorException: dimensions mismatch: ODE
> problem has dimension 0, initial state vector has dimension 6
>         at
> org.apache.commons.math.ode.AdaptiveStepsizeIntegrator.sanityChecks(AdaptiveStepsizeIntegrator.java:177)
>         at
> org.apache.commons.math.ode.EmbeddedRungeKuttaIntegrator.integrate(EmbeddedRungeKuttaIntegrator.java:179)
> 
> Did I forget to set the dimension? If so, how is this done?

The problem you pass to the integrator implements the
FirstOrderDifferentialEquations interfaces, which has a getDimension()
method. This method must provide the dimension of the set of
differential equations it computes. In your case, I guess you should have:

public int getDimension() {
  return 6;
}

This must be consistent with the dimension of the state vector.

Luc

> 
>  
> 
> Angelo
> 
> 


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