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## Re: Solving a trivial ODE with lsode?

 From: Geraint Paul Bevan Subject: Re: Solving a trivial ODE with lsode? Date: Thu, 12 Feb 2004 15:46:01 +0000 User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6b) Gecko/20031221 Thunderbird/0.4

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Dirk Koschützki wrote on 02/12/04 12:09:
| Hello,
|
| I'm trying to solve a trivial ODE with octave (2.1.35) . This example is
| used just to get a feeling for octave.
|
| My problem is: I did not get the correct solution.
|

The correct solution of \int_0^{20} 2x dt" is not x^2, so your target
function 'quadrat' is not what the result of using lsode should show.

Your initial state is 0. At t=0, the derivative is 2*0=0, hence the next
~ value of the state is also 0.

Integrating a system that has no external inputs and is in a steady
state (dx/dt=x=0) will not give you a very interesting simulation.

- --
Geraint Bevan
http://www.mech.gla.ac.uk/~gbevan

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