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Date: Sun, 17 Aug 2008 08:39:00 -0000
From: Tuomo Keskitalo <Tuomo.Keskitalo@iki.fi>
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Subject: GSL ode-initval development
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Hello all,

I've been thinking about adding some implicit one step solvers for GSL 
ode-initval. However, I think the current ode-initval framework is not 
too easy to use for implicit solvers.

Implicit solvers result in a group of algebraic non-linear equations, 
for which there exists several solution strategies. The choice of the 
efficient strategy depends on the problem. For example, some modified 
Newton iteration methods are suitable for stiff systems, while 
functional iteration works for non-stiff systems. I would like to give 
the user the freedom to choose the non-linear eq solver separately from 
the stepping method. Does anyone see a way to do this with current 
framework?

I am currently considering to add a new framework part for specifying 
the non-linear equation solver. However, this would break the current 
framework. I wonder if I should write a separate "ode-initval2" library 
because of this. Any comments?

-- 
Tuomo.Keskitalo@iki.fi
http://iki.fi/tuomo.keskitalo