Crystallography Online: the website of the International Union of Crystallography

Dear Colleagues,

  The beam center has been a problem at many times and
in many ways.  There could be a problem in the library,
but the most common source of beam center flips
outside the image is in the handling of the "increasing"
and "decreasing" flags and precedence for the detector axes.

  To help resolve this, and to help make CBFlib as robust
as possible, I would appreciate test cases that cause
problems.  Since the images involved are large, it
would be best to post them on an ftp or html server
and send the URL, along with the code that is having
trouble getting the center into the right place
on the image.

  Regards,
    Herbert

=====================================================
 Herbert J. Bernstein, Professor of Computer Science
   Dowling College, Kramer Science Center, KSC 121
        Idle Hour Blvd, Oakdale, NY, 11769

                 +1-631-244-3035
                 yaya at dowling.edu
=====================================================

On Thu, 7 Jun 2007, Winter, G (Graeme) wrote:

> Hi All,
>
> While we're on the matter of using Python to access the information in
> the image, I thought I should mention the Diffraction Image library
> maintained by Francois Remacle.
>
> http://www.ccp4.ac.uk/newsletters/newsletter45/articles/DiffractionImage
> .html
>
> This is a general purpose library for accessing information in
> diffraction images of many formats including CBF. Although the API is
> more limited (as it has to be general) the key items describing the
> experiment are available.
>
> At the moment we're just ironing out a small problem with the CBF
> reading, in that one of the beam centre ordinates comes out negative.
> I'm not sure if this is a problem with the example image or the library,
> but I can see the beam centre in the middle of the picture... Has anyone
> seen this problem before?
>
> Anyhow, I just thought I would give this a mention. This is a C++
> library with bindings to both Tcl and Python, again through swig.
>
> Regards,
>
> Graeme
>
> -----Original Message-----
> From: imgcif-l-bounces at iucr.org [mailto:imgcif-l-bounces at iucr.org] On
> Behalf Of Jon Wright
> Sent: 06 June 2007 23:29
> To: imgcif-l at iucr.org
> Subject: [Imgcif-l] Experimental python bindings to CBFlib
>
> Dear Colleagues,
>
> Some experimental python bindings to CBFlib (0.7.7) are now available:
>
> http://blondie.dowling.edu/frs/download.php/297/pycbf.tar.gz
>
> Many thanks to Herbert for hosting these, as well as providing CBFlib
> which is being wrapped up.
>
> The bindings are generated by SWIG and give access to many, but not all,
> of the functions in CBFlib from python. Assuming you've got CBFlib
> already then the download should just add pycbf directory to your CBFlib
> source tree, eg:
>
> %  cd CBFlib
> %  make -f Makefile_Linux all
> %  make -f Makefile_Linux tests
> %  # CBFlib is now up-to-date
> %  wget http://blondie.dowling.edu/frs/download.php/297/pycbf.tar.gz
> %  tar -zxf pycbf.tgz
> %  cd pycbf
> %  python setup.py build
> %  # your platform might be different
> %  cp build/lib.linux-i686-2.4/_pycbf.so .
> %  python pycbf_test1.py
> %  python pycbf_test2.py
> %  python pycbf_test3.py
>
>
> Any feedback would be most welcome!
>
> Best,
>
> Jon
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