Research

researchAs a computational scientist, my primary research interest is to accelerate numerical simulations in science and engineering as efficiently as possible. Given my background and my current affiliation, my primary area of application is micro– and nanoelectronics. However, my interests – thus my concrete research topics – are broad. Here, I discuss my current and most important research topics.

vsc-3_2919_scaled

vsc_3_scaledHigh Performance Computing

I am particularly interested in utilizing high performance computing resources, i.e., supercomputers (like the VSC-3 in Vienna) as well as multi-core workstations and many-core accelerators and co-processors. To that end I investigate and develop algorithms, data structures, and simulators based on shared-memory parallelization techniques (e.g. OpenMP) as well as distributed-memory approaches (e.g. MPI). In particular, I am a long-term contributor to the ViennaCL project, a free open source linear algebra library for multi- and many core architectures.

My publications in this area ..

Accelerated Redistancing MethodsSimpleTrench_distance

Simulating an expanding front is a fundamental step in many computational science and engineering applications, such as image segmentation, brain connectivity mapping, medical tomography, seismic wave propagation, geological folds, semiconductor process simulation, or computational geometry. In my case, I focus my research on applications in the area of semiconductor process simulation, where a redistancing step is a vital and time-critical component of the level set-based surface evolution simulations used, for instance, for plasma etching.

In general, an expanding front originating from a start position is described by its first time of arrival to the points of a domain. This problem can be described by solving the Eikonal equation. I investigate novel methods for solving this equation targeting shared-memory multi- and many-core architectures via, for instance, OpenMP. I particularly focus on the fast iterative method, the semi-ordered fast iterative method, and the fast marching method.

My publications in this area ..

Distributed Quantum Wigner Monte Carlo Simulationsdensity_t50

An attractive new approach to model future nanoelectronic devices is based on the Wigner formalism, which provides an attractive alternative to the non-equilibrium Green’s function formalism. Both stochastic and deterministic methods have been applied to solve the one-dimensional Wigner equation. However, only the Wigner Monte Carlo method, using the signed-particle technique, has made multi-dimensional Wigner simulations viable thus far; a multi-dimensional approach is essential for the simulation of realistic semiconductor devices.

However, the computational efforts of solving the signed-particle-based Wigner Monte Carlo system is significant, introducing the dire need for parallelization. One option is to partition the spatial domain and distribute the thus partitioned workload among the compute units. To allow for a scalable approach, distributed-memory architectures (e.g. supercomputers) are targeted using MPI. The concepts of classical domain decomposition have been adapted and applied to the signed-particle Wigner Monte Carlo simulator yielding excellent speed-up allowing to obliterate the otherwise multi-day simulation period to the minutes to hours regime. Aside of the parallelization techniques I oversee the free open source ViennaWD simulation package, which contains the simulator.

My publications in this area ..

Mesh Generationflexfet_fancy_nobg

To be able to solve mathematical models for complicated structures (e.g. a FlexFET), the geometrical description – describing the structure – needs to be discretized, i.e., the simulation domain needs to be partitioned into a finite set of elements. The mathematical models, e.g. PDEs, are then evaluated on those elements respecting a certain set of boundary conditions and possible initial guesses. The step of discretizing the simulation domain is called mesh generation which introduces its own set of intricate challenges, like accuracy and speed. In the earlier days I started investigating software aspects to interface with several mesh generation tools and use them to build advanced meshing workflows, aiding the end-users in creating adequate meshes for their simulations. This work birthed the free open source ViennaMesh software package. Nowadays, I am focusing on supervising younger colleagues in this area.

My publications in this area ..

Recent Posts

Back with the 2016 Google Summer of Code at TU Wien

GSoC2016Logo

After being ordered to the bench in 2015 (to give others a chance to participate as well), we made it back! The TU Wien – for the fifth time now – participates this year again in Google’s Summer of Code program with the loose interest group “Computational Science and Engineering at TU Wien”. Our group is composed of several departments of our university and thus offers students a diverse set of free open source projects to work on. By now, we can look back on a decent history: We have already participated in 2011, 2012, 2013, 2014 and so far supervised 40 international students with a great interdisciplinary team of university staff.

For this year, visit our org(anization) at the program website and checkout our project ideas. Selected students will have the excellent opportunity to enter an internationally highly visible student summer program, extend their programming skills, get in touch with open source development teams in the area of science and engineering, and on top of that Google will hand out USD 5 500 to each successful student. Interested students should get in touch with us via our mailing list as soon as possible to prepare their application material; submission deadline is March 25.

For us, the university, participating in the Google Summer of Code allows us to advance our open source code, which in turn is desperately needed to advance our science with a reasonable pace. We get access to highly motivated students who are eager to learn and bring new ideas and impulses to the table, which for obvious reasons is of great interest to us. It also allows us to spread the awareness about the importance of open source code for science and engineering and educate future research software engineers. This is what I call a win-win.

The Austrian media picked up on the topic as well – here are some links in German:

  1. VSC Seminar Talk: Modern Multi-Core Architectures for Supercomputing Comments Off on VSC Seminar Talk: Modern Multi-Core Architectures for Supercomputing
  2. Opening of my Christian Doppler Laboratory Comments Off on Opening of my Christian Doppler Laboratory
  3. NVIDIA GPU Research Center Comments Off on NVIDIA GPU Research Center
  4. HPC 2016 Comments Off on HPC 2016
  5. VSC School Kick-Off Leave a reply
  6. IUE Summer of Code 2015 Leave a reply
  7. Open source research software – my (reused) “two” cents Leave a reply
  8. LSSC 2015 Leave a reply
  9. HPC 2015 Leave a reply