​This book constitutes the refereed proceedings of the 11^th International Conference on Parallel Computational Technologies, PCT 2017, held in Kazan, Russia, in April 2017.

The 24 revised full papers presented were carefully reviewed and selected from 167 submissions. The papers are organized in topical sections on high performance architectures, tools and technologies; pa

rallel numerical algorithms; supercomputer simulation.

This book constitutes the refereed proceedings of the 12th International Conference on Parallel Computational Technologies, PCT 2018, held in Rostov-on-Don, Russia, in April 2018.The 24 revised full papers presented were carefully reviewed and selected from 167 submissions.