[Imgcif-l] proposed change in first line of imgcif files
Harry Powell
harry at mrc-lmb.cam.ac.uk
Thu Oct 2 13:19:12 BST 2008
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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Harry
--
Dr Harry Powell, MRC Laboratory of Molecular Biology, MRC Centre,
Hills Road, Cambridge, CB2 0QH
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