structure factor interpolation
Hi, I am looking for a function that would allow me to interpolate the structure factors values in between the reciprocal lattice points (h,k,l not integer) so that I can get the reciprocal map not of the whole crystal but of "only one" unit-cell. Is there a simple way to do that in the cctbx ? Thanks Celine -- Dr. CĂ©line Besnard EPFL - SB - IPMC - LCR2 CH-1015 Lausanne Suisse e-mail : [email protected] Tel : +41(0)21.693.05.41 Fax : +41(0)21.693.05.04 http://lcr.epfl.ch
Hi Celine,
the short answer is "no, sorry".
But I'm asking around if we could move code from elsewhere.
We do have "eight_point_interpolation" code in cctbx/maptbx, incl. Python bindings,
in case that could be useful.
Ralf
----- Original Message ----
From: celine Besnard
Hi Ralf, Celine, Perhaps I have misunderstoond the question.... Isn't it equivalent for the unit cell to be expanded in real space so that the lattice points are compressed in reciprocal space? Just expand the structure to P1 and keep the atoms fixed in real space orthogonal angstrom co-ordinates. Like this it seems you can get the reciprocal space points whereever you want? All the best, Jon Ralf W. Grosse-Kunstleve wrote:
Hi Celine, the short answer is "no, sorry". But I'm asking around if we could move code from elsewhere. We do have "eight_point_interpolation" code in cctbx/maptbx, incl. Python bindings, in case that could be useful. Ralf
----- Original Message ---- From: celine Besnard
To: [email protected] Sent: Friday, October 31, 2008 2:57:44 AM Subject: [cctbxbb] structure factor interpolation Hi,
I am looking for a function that would allow me to interpolate the structure factors values in between the reciprocal lattice points (h,k,l not integer) so that I can get the reciprocal map not of the whole crystal but of "only one" unit-cell. Is there a simple way to do that in the cctbx ?
Thanks
Celine _______________________________________________ cctbxbb mailing list [email protected] http://www.phenix-online.org/mailman/listinfo/cctbxbb
Hi Jon,
Perhaps I have misunderstoond the question.... Isn't it equivalent for the unit cell to be expanded in real space so that the lattice points are compressed in reciprocal space? Just expand the structure to P1 and keep the atoms fixed in real space orthogonal angstrom co-ordinates. Like this it seems you can get the reciprocal space points whereever you want?
I think that's correct, but you need to decide how big to make the pseudo unit cell, and how to interpolate. I looked at the phaser code, where they have simple two-point interpolation, four-point and eight-point. We have cctbx.crystal.non_crystallographic_symmetry(), which uses cctbx.uctbx.non_crystallographic_unit_cell() to do the actual work, and cctbx.uctbx.non_crystallographic_unit_cell_with_the_sites_in_its_center() which moves the coordinates around. And we have cctbx.maptbx.non_crystallographic_eight_point_interpolation, implemented in cctbx/maptbx/eight_point_interpolation.h . Hope this helps. Ralf
participants (3)
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celine Besnard
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Jon Wright
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Ralf W. Grosse-Kunstleve