Description
Many space groups have degenerate choices of origins. Some have only a small number (ie 2) possible origins. Whereas others have a continuum of origins along one or more axis. These are called polar space groups. Given two isomorphous sets of structure factors with different origins, it is possible to align the resulting electron density maps by altering the phases to be consistent. It turns out this is equivalent to the image registration problem in computer vision which can be efficiently solved in fourier space (see: https://scikit-image.org/docs/stable/api/skimage.registration.html#skimage.registration.phase_cross_correlation). Other solutions to this problem rely on protein structures which is undesirable for some applications.
A detailed discussion of this is including some example implementations is in rs-station/reciprocalspaceship#31 (comment). In the issue on rs, we decided this problem was out of scope for rs and should reside in rs-booster. The last two comments are the most relevant.
I think this project requires
- an api level function which accepts two data sets and returns the optimal phase shifts to align them
- a command line script that accepts a pair of mtzs along with column keys and outputs a translated version of one mtz
My question is whether anyone wants to tackle this? I'm looking at you,