Serial crystallography records still diffraction patterns from single, randomly oriented crystals, then merges data from hundreds or thousands of them to form a complete data set. To process the data, the diffraction patterns must first be indexed, equivalent to determining the orientation of each crystal. A novel automatic indexing algorithm is presented, which in tests usually gives significantly higher indexing rates than alternative programs currently available for this task. The algorithm does not require prior knowledge of the lattice parameters but can make use of that information if provided, and also allows indexing of diffraction patterns generated by several crystals in the beam. Cases with a small number of Bragg spots per pattern appear to particularly benefit from the new approach. The algorithm has been implemented and optimized for fast execution, making it suitable for real-time feedback during serial crystallography experiments. It is implemented in an open-source C++ library and distributed under the LGPLv3 licence. An interface to it has been added to the CrystFEL software suite.

中文翻译：

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XGANDALF – 用于格子查找的扩展梯度下降算法

串行晶体学记录来自单个随机取向晶体的静态衍射图案，然后合并来自数百或数千个晶体的数据以形成完整的数据集。为了处理数据，必须首先对衍射图案进行索引，相当于确定每个晶体的方向。提出了一种新颖的自动索引算法，在测试中通常比当前可用于此任务的替代程序提供更高的索引率。该算法不需要晶格参数的先验知识，但可以利用该信息（如果提供），并且还允许对光束中的多个晶体生成的衍射图案进行索引。每个图案具有少量布拉格点的情况似乎特别受益于新方法。该算法已经过实现和优化，可快速执行，使其适合串行晶体学实验期间的实时反馈。它在开源 C++ 库中实现，并根据 LGPLv3 许可证分发。它的接口已添加到晶体FEL软件套件。