Robust powder auto-indexing using many peaks

A new powder auto-indexing method for the CONOGRAPH software [Oishi-Tomiyasu (2013). Acta Cryst. A69, 603-610] can carry out exhaustive powder auto-indexing in a short time, even if the q values of many peaks are used, with sufficient consideration given to their observational errors. This article explains that the use of many q values is essential to make powder auto-indexing robust against dominant zones and missing or false peaks in the input. Results from CONOGRAPH for 25 real diffraction patterns, including difficult cases, are presented. Owing to a sorting criterion for zones defined in the previous article, the computation times were reduced by a factor of between 18 and 250, and exhaustive powder auto-indexing was completed in 5 min at most.