[SciPy-User] Why does scipy.integrate.odeint still provide a result even after "repeated convergence failures"?

[Sturla Molden]

See e.g. this:

http://webber.physik.uni-freiburg.de/~jeti/papers/04140671.pdf



On 12/05/15 14:36, Sturla Molden wrote:
> Are you trying to fit an ODE or just solve an ODE with known parameters?
>
> Fitting parameters by solving an ODE can be a notoriously difficult
> problem with respect to convergence. There are methods such as "multiple
> shooting" which can improve the situation. But fitting an ODE is often
> an ill-posed problem.
>
>
> Sturla
>
>
>
> On 12/05/15 07:44, Brian Merchant wrote:
>> Hi Warren,
>>
>> Just an update: I was able to "zero" in on the portion of the model that
>> causes the issue (I set the ode function to just return 0 for every
>> other variable, except the one that causes issues).
>>
>> I can't find an error in the Python code responsible for calculating the
>> derivative for that variable (I stepped through it, it simply implements
>> a Hill equation:
>> http://en.wikipedia.org/wiki/Hill_equation_%28biochemistry%29), and the
>> results provided by odeint in the end don't  seem *obviously* out-of-whack.
>>
>> Brian
>>
>> On Mon, May 11, 2015 at 9:52 PM, Warren Weckesser
>> <warren.weckesser at gmail.com <mailto:warren.weckesser at gmail.com>> wrote:
>>
>>
>>
>>      On Tue, May 12, 2015 at 12:43 AM, Brian Merchant
>>      <bhmerchant at gmail.com <mailto:bhmerchant at gmail.com>> wrote:
>>
>>          Hi all,
>>
>>          Why does scipy.integrate.odeint still provide a result even
>>          after "repeated convergence failures"? Is this result still of use?
>>
>>
>>
>>      Which version of scipy are you using?  Can you give a short example
>>      that demonstrates the problem?
>>
>>      Warren
>>
>>
>>          Kind regards,
>>          Brian
>>
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