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[Octave-bug-tracker] [bug #49408] ode{23, 45} option "Refine" has no eff
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From: |
Carlo de Falco |
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Subject: |
[Octave-bug-tracker] [bug #49408] ode{23, 45} option "Refine" has no effect |
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Date: |
Sat, 17 Dec 2016 20:33:36 -0000 |
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User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:49.0) Gecko/20100101 Firefox/49.0 |
Follow-up Comment #2, bug #49408 (project octave):
Clarification about the different choice of principal timesteps.
With odefun set to
myfun = @(t, y) 1;
the ODE could be integrated exactly in only one step,
so the timestep size is grown by the maximum factor allowed
at each step.
In Octave the maximum factor is
facmax = 1.5;
while from the output of this test it appears to be set to 5 in Matlab.
A large value of facmax can help with very simple problems
but can lead to many timestep rejections in practical cases.
This is more of a problem in Octave than in Matlab because of JIT so it is
fair for Octave to be more conservative.
Therefore the issue here is indeed only the missing refinement steps and not
the timestep selection procedure.
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