Hi Valentin,
This is extremely helpful - thank you for providing these tweaks. I hope
you don't mind if I incorporate this.
(And sorry for the typos - I am normally better at testing.)
Christoph
On Sunday, 30 November 2014 20:54:40 UTC, Valentin Churavy wrote:
>
> I found a second error in lj_cstyle
>
> t is calculated wrongly:
> t = 1./s*s*s != 1/s^3
>
> It probably should be t = 1.0 / (s * s * s)
>
> t = 1.0 / (s*s*s)
> E += t*t - 2.*t
> dJ = -12.0 *(t*t - t) / s
>
> cstyle is on my machine still two times faster then my optimized variant
> of jl_pretty
>
> Best Valentin
>
> On Sunday, 30 November 2014 20:54:58 UTC+1, Valentin Churavy wrote:
>>
>> Nice work!
>>
>> Regarding the pretty Julia version of Lennard-Jones MD.
>>
>> You can shape of another second (on my machine) by not passing in the lj
>> method as a parameter, but directly calling it.
>>
>> I tried to write an optimize version of your lj_pretty function by
>> analysing it with @profile and rewriting the slow parts. You can see my
>> results here: https://gist.github.com/vchuravy/f42f458717a7a49395a5
>> I went step for step through it and applied one optimization at a time.
>> You can also see the time computation time spend at each line as a comment.
>> Mostly I just removed temporary array allocation and then applied your math
>> optimization.
>>
>> One question though. In lj_cstyle(x) you calculate dJ = -12.*(t*t - t) *
>> s , shouldn't it be dJ = -12.*(t*t - t) / s?
>>
>> Kind regards,
>> Valentin
>>
>>
>>
>>
>>
>> On Sunday, 30 November 2014 12:51:31 UTC+1, Christoph Ortner wrote:
>>>
>>> Belated update to this thread:
>>>
>>> I have now finished a first draft of three tutorial-like numerical PDE
>>> notebooks; they can be viewed at
>>> http://homepages.warwick.ac.uk/staff/C.Ortner/index.php?page=julia
>>> I have two more coming up in the near future, one on spectral methods,
>>> the other on an optimisation problem. For the moment, I am using them
>>> primarily for my research group to learn Julia, and to show it to
>>> colleagues when they are interested.
>>>
>>> Q1: May I use the Julia logo on that website, as well as for any
>>> tutorials / courses that I teach based on Julia?
>>>
>>> Q2: Eventually I think it would be good to have a "Julia Examples" page
>>> such as
>>> http://www.mathworks.com/examples/
>>>
>>> Q3: I'd of course be interested in feedback.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
