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Re: [Imgcif-l] proposed change in first line of imgcif files

Hi

My view on this is that in an ideal world, anything written in the  
comments should agree with what is in the CIF tags. In the event that  
there is a difference, the CIF tags should be the ones that the data  
processing program relies on. In a less than ideal world, I would hope  
and expect the same program to be used to write the comment section  
and the CIF tag section  in the same pass using the same data. But  
hope and expectation are often not met...

So if there is an error in the comment section (and the CIF tags are  
correct), and the processing program relies on that information rather  
than the CIF tags, that's probably a shortcoming of the data  
processing program, and that is something that could conceivably be  
dealt with, but really shouldn't have to be.

Practically, I find myself working with a program that uses the header  
information in image files (this is a good thing, in my opinion,  
because it makes so much easier for the program user)- reading this  
information and interpreting it takes time, and I'd like to reduce  
this time to a minimum; so I'd prefer to parse/interpret once and not  
have to worry about comparing comment sections with CIF tags.

Does this help?

>
> I'm *not* saying that we shouldn't have a statement of how the frame  
> data
> should be interpreted right there in the first line.  I'm *not*  
> saying that
> a program which uses this information must then read the relevant  
> tags as
> well to check for conflicts.  I *am* saying that if, somehow, the  
> datablock
> tags and the header mismatch, a program which relies on the header  
> might
> fail if the header is in error.  Of course, if instead the tags are in
> error, then it will not fail.  Where is the issue?  Harry, (if you  
> are still
> reading along), is this an acceptable position from your point of  
> view?
>
>>
>>
>> I think it would be fine to move CIF in the direction of really being
>> a standard.  The ISO rules are given at
>>
>>
>> http://www.iso.org/iso/standards_development/processes_and_procedures/how_are_standards_developed.htm
>>
>> ANSI has similar guidelines.  The standards process in time- 
>> consuming and
>> involves a great deal of consensus building.  I think it would be  
>> worth
>> trying to do.
>
>
> I do appreciate the need for consensus, but at the moment it seems  
> that you
> and I are the only ones searching for consensus. I am also thinking  
> that the
> time has come to instigate some sort of standards process.  Are you  
> thinking
> of CIF becoming an actual ISO or ANSI standard, or rather of   
> implementing
> similar processes within the auspices of the IUCr?
>
> Best wishes,
> James.
>
>
> -- 
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> F +61 (02) 9717 3145
> M +61 (04) 0249 4148
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Harry
-- 
Dr Harry Powell, MRC Laboratory of Molecular Biology, MRC Centre,  
Hills Road, Cambridge, CB2 0QH



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