For this interview, I reached out to Janus Juul Eriksen, a Ph.D. fellow at Aarhus University in Denmark. Janus is a chemist by trade without any formal education in computer science; but he is getting up to 12x speed-up compared to his CPU-only code after modifying less than 100 lines of code with one week of programming effort.
How did he do this? He used OpenACC.
OpenACC is a simple, powerful and portable approach for researchers and scientists who need to rapidly boost application performance for faster science while minimizing programming. With OpenACC, the original source code is kept intact, making the implementation intuitively transparent and leaving most of the hard work to the compiler.
NVIDIA recently announced the new OpenACC Toolkit, an all-in-one suite of parallel programming tools, that helps researchers and scientists quickly accelerate applications.
“OpenACC is much easier to learn than OpenMP or MPI. It makes GPU computing approachable for domain scientists,” says Janus. “Our initial OpenACC implementation required only minor efforts, and more importantly, no modifications of our existing CPU implementation.”
Janus is part of the research team developing the quantum chemistry code LSDalton, a massively parallel and linear-scaling program for the accurate determination of energies and other molecular properties for large molecular systems.
In need of speed, the LSDalton team was awarded an INCITE allocation which gave them access to Oak Ridge National Laboratory’s Titan supercomputer. With this, they needed to find a way to use the power of the supercomputer: enter OpenACC. Demonstrating success on Titan with their GPU-accelerated code, they were recently one of 13 application code projects selected to join the Center for Accelerated Application Readiness (CAAR) program. This means they will be among the first applications to run on Summit, the new supercomputer debuting in 2018 which will deliver more than five times the computational performance of Titan’s 18,688 nodes.
This access will enable the research team to simulate larger molecular structures at higher accuracy, ultimately accelerating discoveries in materials and quantum chemistry.