Guest Editorial: Parallelism in Algorithms and Architectures

This special issue originated from select papers from the 21st ACM Symposium on Parallelism in Algorithms and Architectures (SPAA), which was held August 11–13, 2009 in Calgary, Canada. The papers were selected by the editors based on evaluations from the program committee. The authors were invited to submit extended journal versions of their SPAA papers, and these submissions were rigorously evaluated using the standard review process for the journal. We thank the authors and reviewers for their hard work.