leonarski_f
996d8e7d41
The 44 lattice characters come in two types - all-acute reduced cells and all-obtuse ones - and the search skips the type-1 characters whenever the reduced beta is within the angle tolerance of 90 degrees, because at that point the two types are no longer distinguishable and only the type-2 statement of a character is safe to test. But a cell whose reduced beta really is 90 within tolerance can itself reduce EITHER way, and an all-acute one then matches no character at all: the type-1 ones were skipped and the type-2 ones are written for the obtuse setting. It falls through to triclinic, and a centred lattice loses its centring. Measured on a C-centred monoclinic crystal whose reduced beta sits 0.07 degrees from 90. Its free-refined cell came back acute or obtuse depending on the last digits of the refinement - a sub-pixel change in the beam centre was enough - and with it the lattice was read as C-centred monoclinic or as triclinic, and the run merged in C2 or in P1 with twice the asymmetric unit. In the obtuse setting the character matches with residuals of 0.01 to 0.14 degrees against a 3 degree tolerance, at every geometry tried; there was never any doubt about the lattice, only about which side of the boundary the reduction landed on. So when nothing matched and the cell is acute with beta at the boundary, present it in the obtuse setting and match once more. Negating a and c leaves the lattice and beta alone and turns alpha and gamma into their supplements. The second attempt runs only where the first found nothing, so no lattice that is classified today can be re-classified by this.
Jungfraujoch
Application to receive data from the PSI JUNGFRAU and EIGER detectors.
All documentation is now placed in docs/ subdirectory and for the current version hosted on Jungfraujoch Read The Docs page.