We consider the problem of structure prediction for sparse LU factorization with partial pivoting. In this context, it is well known that the column elimination tree plays an important role for matrices satisfying an irreducibility condition, called the strong Hall property. Our primary goal in this paper is to address the structure prediction problem for matrices satisfying a weaker assumption...

Split-merge moves are a standard component of MCMC algorithms for tasks such as multitarget tracking and fitting mixture models with unknown numbers of components. Achieving rapid mixing for split-merge MCMC has been notoriously difficult, and state-of-the-art methods do not scale well. We explore the reasons for this and propose a new split-merge kernel consisting of two sub-kernels: one combi...

We prove two complexity results about the H-index concerned with the Google scholar merge operation on one’s scientific articles. The results show that, although it is hard to merge one’s articles in an optimal way, it is easy to merge them in such a way that one’s H-index increases. This suggests the need for an alternative scientific performance measure that is resistant to this type of manip...

Which merges files better: the SAS  DATA Step or SAS SQL? Traditionally, the only way to merge files in SAS was via the SAS DATA Step. Now SAS provides a Structured Query Language (SQL) facility which also merges files. This tutorial compares and contrasts these two merge facilities. It examines the pros and cons of each merge technique. It looks at DATA Step code to perform specific merges an...