[phenixbb] Weight optimization

[Jianghai Zhu]

Are these limits the max values for a single bond or angle? or they are the targets for the whole structure? If they are the latter, then 0.02 and 2 came from the classic Engh and Huber paper. And I agree that the lower the resolution, the tighten these constraints should be.  

-- Jianghai




On May 26, 2010, at 11:30 AM, Pavel Afonine wrote:

> Hi Jianghai,
> 
>> Yes, these limits fixed the problem.  
> 
> thanks for letting know, I'm glad it worked for you!
> 
>> But the default values should be 0.02 and 2, respectively, I believe.
> 
> Well, I guess better to have it resolution dependent, and best to have it local per bond or so. I have no intention to open another can of worms, but where those 0.02 and 2 come from? Can you really see that level of details at say 2.5A resolution and lower? I guess at that resolutions they should be both zero. In contrast, at higher resolution larger deviations are justified just by the data and so larger margins in restraints should be allowed. I know there is a heap of good papers on this matter, including the recent ones, and there are long threads on bb, but to me this question is still somewhat open. May be someone on the board can thoroughly/convincingly comment on this, summarizing all previous discussions?
> 
> Anyway, I agree, 0.05 and 3.5 is probably too generous.
> 
> All the best!
> Pavel.
> 
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