Monitoring and Classification Framework for LCLS data.
John developed the Accelerated Rank Adaptive Matrix Sketching (ARAMS) algorithm to facilitate the analysis of large-scale datasets generated by the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory (Winnicki et al., 2024).
References
2024
Data Reduction
Matrix Sketching for Online Analysis of LCLS Imaging Datasets
John Winnicki, Frédéric Poitevin, Haoyuan Li, and 1 more author
X-ray light source facilities such as the Linac Coherence Light Source (LCLS) at SLAC National Accelerator Laboratory generate massive amounts of data that need to be analyzed quickly to inform ongoing experiments. The analysis of data streams coming from various parts of the instrument has potential to feed back into instrument operation or experiment steering. For example, shot-to-shot images of the beam profile inform on the quality of the beam delivery while downstream data read from large area detectors inform on the state of diffraction experiments carried on samples of interests at various beamlines. However, the high repetition rate and high dimensionality of these data streams make their analysis challenging, both in terms of scalability and interpretability. In this work, we propose an image monitoring and classification framework that follows a three-stage process: dimensionality reduction using principal component analysis on a matrix sketch, visualization using UMAP, and clustering using OPTICS. In the dimensionality reduction step, we combine the Priority Sampling algorithm with a modified Frequent Directions algorithm to produce a rank-adaptive accelerated matrix sketching (ARAMS) algorithm, wherein practitioners specify the target error of the sketch as opposed to the rank. Furthermore, the framework is parallel, enabling real-time analysis of the underpinning structure of the data. This framework demonstrates strong empirical performance and scalability. We explore its effectiveness on both beam profile data and diffraction data from recent LCLS experiments.
