Publications by Type

Publications in preparation or review

  • Efficient Algorithms for Collective Operations with Notified Communication in Shared Windows. Muhammed Abdullah Al Ahad, Christian Simmendinger, Roman Iakymchuk, Tiberiu Rotaru, Erwin Laure, Stefano Markidis. Submitted to the Alternatives to MPI workshop at SC18. Zenodo preprint: zenodo.1346121 (Zenodo doi)
  • Convergence analysis of a two-step method for the nonlinear least squares problem with decomposition of operatorStepan Shakhno, Roman Iakymchuk, and Halyna Yarmola. Submitted to the Journal of Computational and Applied Mathematics. HAL ID: hal-01857847 (pdf)
  • Applications, reproducibility, numerical analysis and performance of the Feltor code and library on parallel computer architectures. Matthias Wiesenberger, Lukas Einkemmer, Markus Held, Albert Gutierrez-Milla, Xavier Saez, Roman Iakymchuk. Submitted to CPC. arXiv preprint arXiv:1807.01971 (pdf)
  • Interoperability Strategies for GASPI and MPI in Large Scale Scientific Applications. Christian Simmendinger, Dana Akhmetova, Luis Cebamanos, Tiberiu Rotaru, Mirko Rahn, Stefano Markidis, Erwin Laure, Valeria Bartsch, Roman Iakymchuk. IJHPCA. Accepted on June 29th (Zenodo doi)
  • Hierarchical Approach for Deriving a Reproducible LU factorization. Roman Iakymchuk, Stef Graillat, Devid Defour, and Enrique S. Quintana-Orti. IJHPAC. Accepted on August 17th. HAL preprint: hal-01419813 (pdf)

Journal Articles

  • A Taxonomy of Task-Based Parallel Programming Technologies for High-Performance Computing. Peter Thoman, Kiril Dichev, Thomas Heller, Roman Iakymchuk, Xavier Aguilar, Khalid Hasanov, Philipp Gschwandtner, Pierre Lemarinier, Stefano Markidis, Herbert Jordan, Thomas Fahringer, Kostas Katrinis, Erwin Laure, Dimitrios S. Nikolopoulos. Journal of Supercomputing, pp 1-13, 2018. Open Access. (doi)
  • An Iterative Method for Solving Nonlinear Least Squeares Problems with Nondifferentiable Operator. Stepan Shakhno, Roman Iakymchuk, and Halyna Yarmola. Matematychni Studii. 2017, Vol. 48, No. 1, 97-107. (doi) HAL ID: hal-01709582 (pdf)
  • Convergence Analysis of a Two-Step Modification of the Gauss-Newton Method and its Application. Roman Iakymchuk, Stepan Shakhno, and Halyna Yarmola. Journal of Computational and Applied Mathematics. 2017, Vol. 126, No. 3, 61-74. (online) HAL ID: hal-01709878 (pdf)
  • A Performance Characterization of Streaming Computing on Supercomputers. Stefano Markidis, Ivy Bo Peng, Roman Iakymchuk, Erwin Laure, Gokcen Kestor, and Roberto Gioiosa. Procedia Computer Science, 80:98-107, 2016.
  • Reproducible and Accurate Matrix Multiplication. Roman Iakymchuk, David Defour, Sylvain Collange, and Stef Graillat. Lecture Notes of Computer Science. Scientific Computing, Computer Arithmetic, and Validated Numerics: 16th International Symposium, SCAN 2014, Würzburg, Germany, September 21-26, 2014. Revised Selected Paper. Vol. 9553, 2016, 126-137. (doi) HAL ID: hal-01102877 (pdf)
  • Numerical Reproducibility for the Parallel Reduction on Multi- and Many-Core Architectures. Sylvain Collange, David Defour, Stef Graillat, and Roman Iakymchuk. Parallel Computing, 49:83-97, 2015 (doi). HAL ID: hal-00949355v4 (pdf)
  • Modeling Performance through Memory-Stalls. Roman Iakymchuk and Paolo Bientinesi. ACM SIGMETRICS Performance Evaluation Review. 2012, Vol. 40, 86--91 (web | pdf)
  • On a Secant Type Method for the Nonlinear Least Squares Problem. Stepan Shakhno, Oleksandra Gnatyshyn, and Roman Iakymchuk. Journal of Numerical and Applied Mathematics. 2009, Vol. 97, 112-121 (pdf)
  • About Two-Step Modification of Gauss-Newton Method at the Generalized Lipschitz Conditions for Solving the Nonlinear Least Squares Problem. (in Ukrainian) Stepan Shakhno and Roman Iakymchuk. Math. Visnyk of the Shevchenko Scientific Society. 2009, Vol. 6, 277-287 (web)
  • One Difference Method with Super-Quadratic Convergence for Solving the Nonlinear Least Squares Problem. (in Ukrainian) Stepan Shakhno, Oleksandra Gnatyshyn, and Roman Iakymchuk. Visnyk of the Lviv Univ. Ser. Applied Math. and Inform. 2007, Vol. 13, 51-59 (web)

Peer-Reviewed Conference Papers

  • Towards a Reproducible Solution of Linear Systems. Roman Iakymchuk, Stef Graillat, Devid Defour, Erwin Laure, and Enrique S. Quintana-Orti. The Computational Reproducibility at Exascale (CRE17) workshop held as part of the Supercomputing Conference (SC17). Denver, Colorado, USA, November 12-17, 2017. HaL ID: hal-01633980 (pdf)
  • A Taxonomy of Task-Based Technologies for High-Performance Computing. Peter Thoman, Khalid Hasanov, Kiril Dichev, Roman Iakymchuk, Xavier Aguilar, Philipp Gschwandtner, Erwin Laure, Stefano Markidis, Herbert Jordan, Pierre Lemarinier, Kostas Katrinis, Dimitrios Nikolopoulosi, and Thomas Fahringer. In: Wyrzykowski R., Dongarra J., Deelman E., Karczewski K. (eds) Parallel Processing and Applied Mathematics. PPAM 2017. Lecture Notes in Computer Science, vol 10778. Springer. pp 264-274. (doi) (preprint)
  • Interoperability of GASPI and MPI in Large Scale Scientific Applications. Dana Akhmetova, Luis Cebamanos, Roman Iakymchuk, Tiberiu Rotaru, Mirko Rahn, Stefano Markidis, Erwin Laure, Valeria Bartsch, Christian Simmendinger. In: Wyrzykowski R., Dongarra J., Deelman E., Karczewski K. (eds) Parallel Processing and Applied Mathematics. PPAM 2017. Lecture Notes in Computer Science, vol 10778. Springer. pp 277-287. (doi) (pdf)
  • Towards Reproducible Blocked LU Factorization. Roman Iakymchuk, Enrique Quintana-Orti, Erwin Laure, and Stef Graillat. Accepted to the REPPAR workshop held as part of the IPDPS conference. Orlando, Florida, USA, May 29 - June 2, 2017. 1598 - 1607. HAL ID: hal-01456307 (pdf)
  • API interoperability among multithreaded MPI and OpenMP tasking in a large scientific code. Dana Akhmetova, Roman Iakymchuk, Orjan Ekeberg, Erwin Laure. Accepted to the HIPS workshop held as part of the IPDPS conference. Orlando, Florida, USA, May 29 - June 2, 2017. 756 - 765.
  • Hierarchical Approach for Deriving a Reproducible LU factorization on GPUs. Roman Iakymchuk, Stef Graillat, Devid Defour, and Enrique S. Quintana-Orti. The Numerical Reproducibility at Exascale (NRE16) workshop held as part of the Supercomputing Conference (SC16). Salt Lake City, Utah, USA, November 13-18, 2016. HaL ID: hal-01382645 (pdf)
  • Combined Newton-Kurchatov method for solving nonlinear operator equations. Halyna Yarmola, Roman Iakymchuk, and Stepan Shakhno. PAMM. Vol. 16. Special issue: Joint Annual Meeting of GAMM and DMV, Braunschweig, Germany, March 7-11, 2016. 719-720 (web). HaL ID: hal-01352436 (pdf)
  • ExBLAS: Reproducible and Accurate BLAS Library. Roman Iakymchuk, Sylvain Collange, Devid Defour, and Stef Graillat. The Numerical Reproducibility at Exascale (NRE15) workshop held as part of the Supercomputing Conference (SC15). Austin, TX, USA, November 15-20, 2015. HaL ID: hal-01202396v2 (pdf)
  • Reproducible Triangular Solvers for High-Performance Computing. Roman Iakymchuk, Sylvain Collange, Devid Defour, and Stef Graillat. In Proceedings of the 12th International Conference on Information Technology: New Generations (ITNG 2015), Special track on: Wavelets and Validated Numerics, April 13-15, 2015, Las Vegas, Nevada, USA. 353-358 (doi). HAL ID: 01116588v2 (pdf)
  • Methods with Successive and Parallel Approximations of Inverse Operator for the Nonlinear Least Squares Problem. Roman Iakymchuk and Stepan Shakhno. PAMM. Vol. 15. Special issue: 86th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), Lecce, Italy, March 23-27, 2016. 569-570 (web)
  • On the Convergence Analysis of a Two-Step Modification of the Gauss-Newton Method. Roman Iakymchuk and Stepan Shakhno. PAMM. Vol. 14. Special issue: 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), Erlangen, Germany, 2014, 813-814 (web)
  • Performance Analysis on Energy Efficient High-Performance Architectures. Roman Iakymchuk and François Trahay. In Proceedings of the 2nd International Conference on Cluster Computing (CC'13). Lviv, Ukraine, June 3-5, 2013, 80-85 (pdf)
  • Execution-Less Performance Modeling. Roman Iakymchuk and Paolo Bientinesi. In the Proceedings of the Second International Workshop on Performance Modeling, Benchmarking and Simulation of High-Performance Computing Systems (PMBS11) held as part of the Supercomputing Conference (SC11). Seattle, USA, November 13th, 2011, 11-12 (pdf)
  • Performance Prediction through Time Measurements. Roman Iakymchuk. In Proceedings of the 1st International Conference on High-Performance Computing (HPC-UA'11). Kyiv, Ukraine, October 12-14, 2011, 26-32. (pdf)
  • Improving High-Performance Computations on Clouds Through Resource Underutilization. Roman Iakymchuk, Jeff Napper, and Paolo Bientinesi. In Proceedings of ACM 26th Symposium on Applied Computing, special track on Cloud Computing. Taichung, Taiwan, March 21-25, 2011, 119-126 (pdf)
  • On a One-Step Modification of Gauss-Newton Method under Generalized Lipschitz Conditions for Solving the Nonlinear Least Squares Problem. Stepan Shakhno and Roman Iakymchuk. PAMM. Vol. 9. Special issue: 80th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), Gdansk, Poland, February 9-13, 2009, 565-566 (web)

Book Chapter

  • HPC on Competitive Cloud Resources. Paolo Bientinesi, Roman Iakymchuk, and Jeff Napper. In Borko Furht and Armando Escalante, editors, Handbook of Cloud Computing. Springer, 2010, 493-516 (pdf)

News Articles

  • Crowded Clouds. Jeff Napper, Roman Iakymchuk, and Paolo Bientinesi. HPCwire, August 12th, 2010 (web)
  • HPC Sharing in the Cloud. Jeff Napper, Roman Iakymchuk, and Paolo Bientinesi. HPC in the Cloud, August 12th, 2010 (web)

Invited Talks

  • A Reproducible Solution of Linear Systems. Roman Iakymchuk. Joint work with Erwin Laure, Stef Graillat, and Enrique Quintana-Orti. MS66: Reliable numerical computations in HPC environments at SIAM PP 2018, March 7-10, 2018, Tokyo, Japan.
  • Hierarchical Approach for Deriving a Reproducible LU Factorization. Roman Iakymchuk. Joint work with David Defour, Stef Graillat, Erwin Laure, and Enrique Quintana-Orti. RAIM 2017: 9èmes Rencontre "Arithmétique de l'Informatique Mathématique", October 24-26, 2017, Lyon, France.
  • Reproducibility of Linear Algebra Operations. Roman Iakymchuk. Joint work with David Defour, Stef Graillat, Enrique Quintana-Orti. MS237: Algorithmic Revolution in Post Moore's Era: Auto-Tuning and Accuracy Assurance at SIAM CSE 2017, February 27-March 3, 2017, Atlanta, USA. (pdf)
  • Reproducible and Accurate Algorithms for Numerical Linear Algebra. Roman Iakymchuk. Joint work with Sylvain Collange, David Defour, and Stef Graillat. MS16: Numerical Reproducibility for High-Performance Computing at SIAM PP 2016, April 12-15, 2016, Paris, France.

Poster

  • INTERTWinE: Programming Model INTERoperability ToWards Exascale INTERTWinE Project. TERATEC Forum 2018: European Research Cafe. Ecole Polytechnique, Palaiseau, France, June 19-20, 2018 (poster)
  • Incorporating Sustainable Development into the Desing of a Student Project Zeev Bohbot, Johan Hellsvik, Roman Iakymchuk, Lauren McKee, Rajib Sinha. International Sustainable Campus Network (ISCN 2018). KTH Royal Institute of Technology, Stockholm, Sweden. June 11-13, 2018 (poster)
  • Feltor: Reproducibility and Performance on Modern Hardware Architectures Matthias Wiesenberger, Lukas Einkemmer, Markus Held, Albert Gutierrez-Milla, Xavier Saez, Roman Iakymchuk. The Annual Meeting of the Danish Physical Society. Middelfart, Denmark, June 6-7, 2018 (poster)
  • ExBLAS: Reproducible and Accurate BLAS Library. Roman Iakymchuk, Stef Graillat, Sylvain Collange, and Devid Defour. 7ème Rencontre Arithmétique de l'Informatique Mathématique RAIM 2015. Rennes, France, April 7-9, 2015 (poster)

Short Papers and Abstracts

  • On a two-step method for the nonlinear least squares problem with decomposition of operator. Roman Iakymchuk, Stepan Shakhno, and Halyna Yarmola. In the proceedings of the APAMCS-2018 conference, Lviv, Ukraine, September 26-28, 2018 (pdf)
  • A Task-Based Particle-in-Cell Method with Automatic Load-Balancing using the AllScale Environment. Roman Iakymchuk; Herbert Jordan; Philipp Gschwandtner; Thomas Heller; Peter Thoman; Xavier Aguilar; Thomas Fahringer; Erwin Laure; Stefano Markidis. In the proceedings of the EASC18 Conference, Edinburgh, Scotland, April 17-19, 2018. (Zenodo doi)
  • Interoperability of GASPI and MPI in a large scale Lattice-Boltzmann code. Roman Iakymchuk, Luis Cebamanos, Tiberiu Rotaru, Mirko Rahn, Erwin Laure, Valeria Bartsch, Christian Simmendinger and Stefano Markidis. Accepted to the PGAS workshop at the PPAM conference. Lublin, Poland, September 10 - 13, 2017. (pdf)
  • Towards Fast, Accurate and Reproducible LU Factorization. Roman Iakymchuk, David Defour, and Stef Graillat. In Book of Abstracts of the 17th International Symposium on Scientific Computing, Computer Arithmetic and Validated Numerics (SCAN'16). Uppsala, Sweden, September 26-29, 2016, 59-60 (pdf, slides)
  • A Particle-in-Cell Method for Automatic Load-Balancing with the AllScale Environment. Roman Iakymchuk, Herbert Jordan, Ivy Bo Peng, Stefano Markidis, and Erwin Laure. Exascale Applications and Software Conference (EASC2016), Stockholm, Sweden, April 25-29, 2016 (pdf)
  • A Case Study of the Reproducibility Issues in EigenExa. Roman Iakymchuk, Imamura Toshiyuki, Stef Graillat, Stefano Markidis, and Erwin Laure. Exascale Applications and Software Conference (EASC2016), Stockholm, Sweden, April 25-29, 2016 (pdf)
  • Combined Newton-Kurchatov method for solving nonlinear operator equations. Halyna Yarmola, Roman Iakymchuk, and Stepan Shakhno. In Book of Abstracts of the Joint Annual Meeting of GAMM and DMV, Braunschweig, Germany, March 7-11, 2016, 1243 (pdf)
  • Methods with Successive and Parallel Approximations of Inverse Operator for the Nonlinear Least Squares Problem. Roman Iakymchuk and Stepan Shakhno. In Book of Abstracts of the 86th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM), Lecce, Italy, March 23-27, 2015, 528 (pdf)
  • Reproducible and Accurate Matrix Multiplication for High-Performance Computing. Sylvain Collange, David Defour, Stef Graillat, and Roman Iakymchuk. In Book of Abstracts of the 16th GAMM-IMACS International Symposium on Scientific Computing, Computer Arithmetic and Validated Numerics (SCAN'14). Würzburg, Germany, September 21-26, 2014, 42-43 (pdf)
  • A Reproducible Accurate Summation Algorithm for High-Performance Computing. Sylvain Collange, Devid Defour, Stef Graillat, and Roman Iakymchuk. In Book of Abstracts of the SIAM Workshop on Exascale Applied Mathematics Challenges and Opportunities (EX14) held as part of the 2014 SIAM Annual Meeting. Chicago, Il, USA, July 6-11, 2014 (pdf)
  • On the Convergence Analysis of a Two-Step Modification of the Gauss-Newton Method. Roman Iakymchuk and Stepan Shakhno. In Book of Abstracts of the 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM). Erlangen, Germany, March 10-14, 2014 (pdf)
  • On a One-Step Modification of the Gauss-Newton Method under Generalized Lipschitz Conditions for Solving the Nonlinear Least Squares Problem. Stepan Shakhno and Roman Iakymchuk. In Book of Abstracts of the 85th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM). Gdansk, Poland, February 9--13, 2009
  • About One Modification of Secant Method for Solving the Nonlinear Least Squares Problem (in Ukrainian). Oleksandra Gnatyshyn, Stepan Shakhno, and Roman Iakymchuk. In Book of Abstracts of the 15th National Scientific Conference "Actual Problems in Applied Mathematics and Informatics". Lviv, Ukraine, September 23-25, 2008, 18
  • About an Iterative Difference Modification of the Gauss-Newton Method for Solving the Nonlinear Least Squares Problem (in Ukrainian). Roman Iakymchuk. In Book of Abstracts of the 11th National Students' Scientific Conference in Applied Mathematics and Informatics SSCAMI-2008. Lviv, Ukraine, April 9-10, 2008, 277-278

Ph.D. Thesis

  • Performance Modeling and Prediction for Linear Algebra Algorithms. Advisor: Prof. Paolo Bientinesi, Ph.D. Co-advisor: Prof. Dr. Enrique S. Quitana Ortí. AICES, RWTH Aachen University, August, 2012 (pdf)