As a beamline scientist I must say I am glad that diffraction image data
is not usually stored as ASCII text. In fact, I am slowly warming to
the idea of storing it as not just binary, but compressed formats.
Problem, I'm sure will be that it won't be long before we forget how to
decompress them, as most of the algorithms we are using aren't all that
widespread. Probably around the same time future generations will curse
us for using ASCII instead of unicode, which is a 16-bit standard. I'm
sure we will be reviled for limiting ourselves so, just to save a factor
of two in disk space.
In situations like this I always use the unix "od" command. It makes
everything "human readable" by converting the bytes into strings you can
read. Then it is just a matter of figuring out what the bytes are.
Unfortunately, "od" only decodes floats on the native platform, so if
the mtz is from another platform (Windows vs Linux, for example), then
you might need to do some swapping. Thus far, I have encountered files
that require one of a few swapping strategies in order to make them work:
1 2 3 4 - no swapping
4 3 2 1 - reverse all bytes
3 4 1 2 - swap words and swap bytes within the words
2 1 4 3 - reverse of previous
2-1 1 4 3 - same as last, but if not all zero, decrement byte #2 before
swapping
3 4 1 2+1 - same as 3412, but if not all zero increment byte #2 before
swapping
I'm sure there are other combinations, but the oldest MTZ I have is only
from 1996.
-James Holton
MAD Scientist
On 11/9/2018 4:47 AM, Eleanor Dodson wrote:
Anyone any idea what to do about this?? Created in 1992!!
Seems unreadable..
No CTYP lines input for file: 1
Indices output even if all data items flagged "missing"
Warning, NOT all LABOUT data lines given
Warning: Machine stamp corrupted? Assuming native format.
>>>>>> CCP4 library signal library_file:End of File (Error)
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