decryst: an efficient software suite for structure determination from powder dirtraction

Presented here is decryst, a software suite for structure determination from powder diffraction, which uses the direct-space method, and is able to apply anti-bump constraints automatically and efficiently during the procedure of global optimization using the crystallographic collision detection algorithm by Liu [Acta Cryst. (2017), A73, 414-422]. decryst employs incremental computation in its global-optimization cycles, which results in dramatic performance enhancement. It is also designed with parallel and distributed computing in mind, allowing for even better performance by simultaneous use of multiple processors. Owing to the parallelized usage of the equivalent position combination method [Deng & Dong (2009). J. Appl. Cryst. 42, 953-958] in decryst, it is particularly suitable for determination of structures with mostly unknown bonding relations, and offers some unprecedented opportunities for these structures. decryst is free and open-source software, and can be obtained at https://gitlab.com/CasperVector/decryst/; it strives to be simple yet flexible, in the hope that the underlying techniques could be adopted in more crystallographic applications.