@conference {710,
	title = {Design and Implementation of a Large Scale Tree-Based QR Decomposition Using a 3D Virtual Systolic Array and a Lightweight Runtime},
	booktitle = {Workshop on Large-Scale Parallel Processing, IPDPS 2014},
	year = {2014},
	month = {2014-05},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Phoenix, AZ},
	abstract = {A systolic array provides an alternative computing paradigm to the von Neuman architecture. Though its hardware implementation has failed as a paradigm to design integrated circuits in the past, we are now discovering that the systolic array as a software virtualization layer can lead to an extremely scalable execution paradigm. To demonstrate this scalability, in this paper, we design and implement a 3D virtual systolic array to compute a tile QR decomposition of a tall-and-skinny dense matrix. Our implementation is based on a state-of-the-art algorithm that factorizes a panel based on a tree-reduction. Using a runtime developed as a part of the Parallel Ultra Light Systolic Array Runtime (PULSAR) project, we demonstrate on a Cray-XT5 machine how our virtual systolic array can be mapped to a large-scale machine and obtain excellent parallel performance. This is an important contribution since such a QR decomposition is used, for example, to compute a least squares solution of an overdetermined system, which arises in many scientific and engineering problems.},
	keywords = {dataflow, message-passing, multithreading, QR decomposition, runtime, systolic array},
	author = {Ichitaro Yamazaki and Jakub Kurzak and Piotr Luszczek and Jack Dongarra}
}
@conference {icl:692,
	title = {Virtual Systolic Array for QR Decomposition},
	booktitle = {15th Workshop on Advances in Parallel and Distributed Computational Models, IEEE International Parallel \& Distributed Processing Symposium (IPDPS 2013)},
	year = {2013},
	month = {2013-05},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Boston, MA},
	abstract = {Systolic arrays offer a very attractive, data-centric, execution model as an alternative to the von Neumann architecture. Hardware implementations of systolic arrays turned out not to be viable solutions in the past. This article shows how the systolic design principles can be applied to a software solution to deliver an algorithm with unprecedented strong scaling capabilities. Systolic array for the QR decomposition is developed and a virtualization layer is used for mapping of the algorithm to a large distributed memory system. Strong scaling properties are discovered, superior to existing solutions.},
	keywords = {dataflow programming, message passing, multi-core, QR decomposition, roofline model, systolic array},
	doi = {10.1109/IPDPS.2013.119},
	author = {Jakub Kurzak and Piotr Luszczek and Mark Gates and Ichitaro Yamazaki and Jack Dongarra}
}
