Re: [Yanl-develop] Developer for numerical routines in C++/boost

[Karsten A. <kar...@gm...>]

Hi,

first of all, the source code lives in

https://boost.org/svn/boost/sandbox/odeint

Some examples already exist in the libs/numeric/odeint/examples. There
is also one examples for the Discrete Nonlinear Schroedinger equation
(DNLS). In principle you can take this example and implement it the DNLS
in terms of their real and imaginary values and compare the performance
of both. A basic performance comparison is shown in lorenz_stepper.hpp

You can also do the same with coupled Landau-Stuart oscillators, which
behave like
\dot{A}_k  = ( 1 + i \omega ) A_k - |A_k|^2 A_k + ( c_1 + i c_2 ) (
A_{k+1} - 2 A_k + A_{k-1} )

Up to now, we have only implemented explict ODE solvers, so we are not
very experienced with implicit solvers. So, if you like to implement the
implicit Euler (or Backward Euler), i think the best way is to find an
existing implementation and try to adapt it to our interface.

If you have any question or want to discuss some issues please let us
know. Thanks for your help.

Best regards,

Karsten



杨苏立 Yang Su Li wrote:
> Hi,
> 
> I am interested in doing the following:
> 
> * An example of an extended, complex-valued system (like the discrete
> Nonlinear Schrödinger equation or coupled Landau-Stuart oscillators),
> where the performance of the an implementation in real values is
> compared against an implementation in complex values.
> 
> Or
> 
> * the implict Euler method.
> 
> Please give me more details and requirements.
> 
> Thank you very much :)
> 
> Suli
> 
> 2009/12/11 Karsten Ahnert <kar...@gm...>:
>> Hi Yang,
>>
>> the build system is included and works fine.
>>
>> At the moment we need any of the following:
>>
>> * an example of an extended two dimensional system (like the complex
>> Ginzburg-Landau Equation, the Fermi-Pasta-Ulam system or somethink
>> similar) in which the different matrix type are tested and their
>> preformance is compared.
>>
>> * An example of an extended, complex-valued system (like the discrete
>> Nonlinear Schrödinger equation or coupled Landau-Stuart oscillators),
>> where the performance of the an implementation in real values is
>> compared against an implementation in complex values.
>>
>> * the implict Euler method.
>>
>> * Integration of the boost unit testing system.
>>
>> * or you have some other interesting problems which can be used as examples.
>>
>> Please, let us know what you want to do. Then, we can you more
>> informations about the implementation.
>>
>> Best regards,
>>
>> Karsten
>>
>>
>>
>>
>> 杨苏立 Yang Su Li wrote:
>>> Hi,
>>>
>>> I am sorry for the late reply, but last few weeks I was in my vacation
>>> and had very poor internet access.
>>>
>>> I am not very familar with the boost.build system. But I am happy to
>>> help testing, writing examples or some implicit methods
>>>
>>> Please let me know what I can do.
>>>
>>> Thank you very much.
>>>
>>> Yang Suli
>>>
>>>
>>>
>>> 2009/11/16 Karsten Ahnert <kar...@gm...>:
>>>> Hi,
>>>>
>>>> we discuss everything about yanl our mailing list:
>>>>
>>>> https://lists.sourceforge.net/lists/listinfo/yanl-develop
>>>>
>>>> Please register there. At the moment, we are working on the ODE solvers.
>>>> The code lives in the boost sandbox
>>>>
>>>> https://boost.org/svn/boost/sandbox/odeint
>>>>
>>>>
>>>> and we try to become a subpart of the boost libs. We wrote an article
>>>> about the design of the solvers, which has been posted on codeproject.
>>>> Maybe this is a good introduction for you:
>>>>
>>>> http://www.codeproject.com/KB/recipes/odeint.aspx
>>>>
>>>> At the moment we have several open tasks:
>>>>
>>>> * documentation
>>>> * midpoint methods and some implicit methods
>>>> * build-system for the examples
>>>> * writing examples
>>>> * testing
>>>>
>>>> Please, let us know where you want to contribute to.
>>>>
>>>> Best regards,
>>>>
>>>> Karsten
>>>>
>>>>
>>>> Suli Yang wrote:
>>>>> Message body follows:
>>>>>
>>>>> Hi,
>>>>>
>>>>> I saw your post asking for contribution to yanl.
>>>>>
>>>>> I am a physics Ph.D student who would like to help. I had
>>>>> some experiences in C++ programming in a small group of
>>>>> about 5 co-workers. Though I don't know too much about
>>>>> numerical computing yet...
>>>>>
>>>>> Please let me know what I can do.
>>>>>
>>>>> Suli
>>>>>
>>>>> --
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>>>
>>
> 
> 
>