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Hans Johansen

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Hans Johansen
Computer Systems Engineer
Phone: +1 510 495 2472

Johansen is a researcher in both the Computational Biosciences Group and Applied Numerical Algorithms Group (ANAG). He focuses on scalable numerical and mathematical algorithms applied to problems where the accuracy of dynamics and multi-scale interactions are important. See his ANAG staff page for more.

Journal Articles

Nishant Nangia, Hans Johansen, Neelesh A. Patankar, Amneet Pal Singh Bhalla, "A moving control volume approach to computing hydrodynamic forces and torques on immersed bodies", Journal of Computational Physics, June 29, 2017, doi: 10.1016/j.jcp.2017.06.047

Dharshi Devendran, Daniel T. Graves, Hans Johansen,Terry Ligocki, "A Fourth Order Cartesian Grid Embedded Boundary Method for Poisson's Equation", Communications in Applied Mathematics and Computational Science, edited by Silvio Levy, May 12, 2017, 12:51-79, doi: DOI 10.2140/camcos.2017.12.51

Jared O. Ferguson, Christiane Jablonowski, Hans Johansen, Peter McCorquodale, Phillip Colella, Paul A. Ullrich, "Analyzing the adaptive mesh refinement (AMR) characteristics of a high-order 2D cubed-sphere shallow-water model", Mon. Wea. Rev., November 9, 2016, 144:4641–4666, doi: 10.1175/MWR-D-16-0197.1

P. McCorquodale, P.A. Ullrich, H. Johansen, P. Colella, "An adaptive multiblock high-order finite-volume method for solving the shallow-water equations on the sphere", Comm. App. Math. and Comp. Sci., 2015, 10:121-162, doi: 10.2140/camcos.2015.10.121

D. Devendran, D. T. Graves, H. Johansen, "A higher-order finite-volume discretization method for Poisson's equation in cut cell geometries", submitted to SIAM Journal on Scientific Computing (preprint on arxiv), 2015,

Peter Schwartz, Julie Percelay, Terry J. Ligocki, Hans Johansen, Daniel T. Graves, Dharshi Devendran, Phillip Colella, Eli Ateljevich, "High-accuracy embedded boundary grid generation using the divergence theorem", Communications in Applied Mathematics and Computational Science 10-1 (2015), 83--96. DOI 10.2140/camcos.2015.10.83, March 31, 2015,

Q. Zhang, H. Johansen and P. Colella, "A Fourth-Order Accurate Finite-Volume Method with Structured Adaptive Mesh Refinement for Solving the Advection-Diffusion Equation", SIAM Journal on Scientific Computing, Vol. 34, No. 2. (2012), B179, doi:10.1137/110820105, 2010,

McCorquodale, P., Colella, P., Johansen, H., "A Cartesian Grid Embedded Boundary Method for the Heat Equation on Irregular Domains", J. Comput. Phys. Vol.173 (2001), pp. 620-635, 2001,

Johansen, H., Colella, P., "A Cartesian Grid Embedded Boundary Method for Poisson's Equation on Irregular Domains", J. Comput. Physics, Vol.147, No.1, pp. 60-85, November 1998,

Conference Papers

Tuowen Zhao, Mary Hall, Samuel Williams, Hans Johansen, "Exploiting Reuse and Vectorization in Blocked Stencil Computations on CPUs and GPUs", Supercomputing (SC), November 2019,

Tuowen Zhao, Samuel Williams, Mary Hall, Hans Johansen, "Delivering Performance Portable Stencil Computations on CPUs and GPUs Using Bricks", International Workshop on Performance, Portability and Productivity in HPC (P3HPC), November 2018,

Tuowen Zhao, Mary Hall, Protonu Basu, Samuel Williams, Hans Johansen, "SIMD code generation for stencils on brick decompositions", Proceedings of the 23rd ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming (PPoPP), February 2018,

Bryce Adelstein Lelbach, Hans Johansen, Samuel Williams, "Simultaneously Solving Swarms of Small Sparse Systems on SIMD Silicon", Parallel and Distributed Scientific and Engineering Computing (PDSEC), June 2017,

Bin Dong, Suren Byna, Kesheng Wu, Prabhat, Hans Johansen, Jeffrey N. Johnson, and Noel Keen, "Data Elevator: Low-contention Data Movement in Hierarchical Storage System", The 23rd annual IEEE International Conference on High Performance Computing, Data, and Analytics (HiPC) (Acceptance rate: 25%), December 19, 2016,

Dharshi Devendran, Suren Byna, Bin Dong, Brian van Straalen, Hans Johansen, Noel Keen, and Nagiza Samatova,, "Collective I/O Optimizations for Adaptive Mesh Refinement Data Writes on Lustre File System", Cray User Group (CUG) 2016, May 10, 2016,

Xiaocheng Zou, David Boyuka, Dhara Desai, Martin, Suren Byna, Kesheng Wu, Kushal, Bin Dong, Wenzhao Zhang, Houjun Tang Dharshi Devendran, David Trebotich, Scott, Hans Johansen, Nagiza Samatova, "AMR-aware In Situ Indexing and Scalable Querying", The 24th High Performance Computing Symposium (HPC, January 1, 2016,

Xiaocheng Zou, Kesheng Wu, David A. Boyuka, Daniel F. Martin, Suren Byna, Houjun, Kushal Bansal, Terry J. Ligocki, Hans Johansen, and Nagiza F. Samatova, "Parallel In Situ Detection of Connected Components Adaptive Mesh Refinement Data", Proceedings of the Cluster, Cloud and Grid Computing (CCGrid) 2015, 2015,

J. Ferguson, C. Jablonowski, H. Johansen, R. English, P. McCorquodale, P. Colella, J. Benedict, W. Collins, J. Johnson, P. Ullrich, "Assessing Grid Refinement Strategies in the Chombo Adaptive Mesh Refinement Model", AGU Fall Meeting, San Francisco, CA, December 15, 2014,

Gunther H. Weber, Hans Johansen, Daniel T. Graves, Terry J. Ligocki, "Simulating Urban Environments for Energy Analysis", Proceedings Visualization in Environmental Sciences (EnvirVis), 2014, LBNL 6652E,

Reports

Dharshi Devendran, Daniel T. Graves, Hans Johansen, "A Hybrid Multigrid Algorithm for Poisson's equation using an Adaptive, Fourth Order Treatment of Cut Cells", LBNL Report Number: LBNL-1004329, November 11, 2014,

Thesis/Dissertations

Cartesian Grid Embedded Boundary Finite Difference Methods for Elliptic and Parabolic Partial Differential Equations on Irregular Domains, Johansen, H., 1997,

Posters

D.F. Martin, H.S. Johansen, P.O. Schwartz, E.G. Ng, "Improved Discretization of Grounding Lines and Calving Fronts using an Embedded-Boundary Approach in BISICLES", European Geosciences Union General Assembly, April 10, 2019,