Sweden’s largest supercomputer brought online

The National Supercomputer Centre, NSC, celebrated its 30th birthday by bringing no less than five supercomputers online, the largest of them, Tetralith, currently the most powerful in the Nordic region. The launch also deepens the collaboration between NSC, the Swedish Meteorological and Hydrological Institute (SMHI), and the Norwegian Meteorological Institute (MET Norway).

Matts Karlsson, Roar Skålin, Rolf Brennerfelt, Sven Stafström and Helen Dannetun Cutting the blue/yellow ribbon in unison, from the left: Matts Karlsson, director of NSC, Roar Skålin, director of MET Norway, Rolf Brennerfelt, director general of SMHI, Sven Stafström, director general of the Swedish Research Council, and LiU’s vice-chancellor Helen Dannetun. Göran Billeson

Three Directors General, Vice-Chancellor Helen Dannetun and Matts Karlsson, director of NSC, cut the broad blue/yellow ribbon while silver tape rained down from above. The oldest and largest supercomputer centre in Sweden celebrated 30 years of operation, and the inauguration of the new systems will bring an increase in collaboration between NSC and weather forecasting services in the Nordic region. Both SMHI and MET Norway have invested in supercomputers that have been purchased and installed at NSC.
The other systems inaugurated are Sigma, financed by Linköping University for its academic research, Stratus and Cirrus, two supercomputers for Nordic weather forecasting financed by SMHI and MET Norway, and Nebula, financed by MET Norway for research and development. In total, 2,896 computational servers with 92,288 processor cores and a peak processing speed of 6.2 petaflops (1015 floating point operations per second) are now online.
The hardware is distributed between three separate units running the NSC software. This comprises a lowermost layer that ensures that all the servers function as a cluster, binding them together, and a layer placed above this where the scientific calculations are carried out. 
Niclas Andersson, technology manager, NSCNiclas Andersson, technology manager, NSC Photo credit Göran Billeson
“We have worked hard with the construction during the autumn, and in addition to the software we have had to put in a lot of blood, sweat and tears to make sure that everything functioned without impacting the users”, joked Niclas Andersson, technical manager at NSC.

A Swedish resource

The largest unit, Tetralith, is currently the most powerful supercomputer in the Nordic region, with a maximum processing speed of around 4 petaflops. Tetralith has been financed through SNIC, the Swedish National Infrastructure for Computing, which in turn receives its financing from the Swedish Research Council and from the ten Swedish universities that are members of the collaboration. 
Tetralith is a national resource for Sweden, open for researchers at Swedish institutions of higher education. Those wishing to use Tetralith must apply for computer time to the SNIC allocation committee, SNAC. The chair of SNAC is KTH researcher Philipp Schlatter.
“We are happy to be able to allocate time on Tetralith, and are expecting major new research results”, he said, and described as an example how his own research in the fluid mechanics around aeroplanes and aeroplane wings has been refined and improved, thanks to the continuously increasing computer power available.
Philipp Schlatter, KTH, chairman SNACPhilipp Schlatter, KTH, chairman SNAC Photo credit Göran BillesonPhilipp Schlatter also sent warm thanks to SNIC and the Swedish Research Council for their investment in Tetralith, which will bring significantly improved opportunities to the Swedish research community.
Other examples of research fields that obtain access to significantly greater computing power with the inauguration of Tetralith are the development of new tailored materials, new aircraft models, visualisation and machine learning, simulation of the flow of blood through the heart and blood vessels, and many more.

Decisive collaboration

In addition to financing from SNIC, NSC has a number of collaborations. One of these is a long-standing arrangement with the Saab Group, which was one of the reasons why the NSC, as the first Swedish supercomputer centre, ended up in Linköping. Another important collaboration is that with SMHI, providing resources for weather and climate research. It is precisely the broad expertise and the stable systems at NSC that have led to the collaboration with SMHI and MET Norway now being deepened.
Roar Skålin, director MET NorwayRoar Skålin, director MET Norway Photo credit Göran Billeson“The collaboration between SMHI and MET in both forecasting and the use of supercomputers is important. The forecasts become more accurate, and the collaboration with NSC allows us to use both expertise and resources efficiently”, said Roar Skålin, general director of MET, at the launch.
General director of SMHI, Rolf Brennerfelt, also emphasised how important the collaboration is.
“In recent years, SMHI and the Norwegian Meteorological Institute have developed a unique collaboration in forecasting services. Now we are also investing in common supercomputer facilities. The Finnish Meteorological Institute, FMI, has been included in the collaboration in forecasting since 2017, and we are hoping that a further seven countries in northern Europe will join in the long term”, he said.
More frequent weather forecasts and the ability to explore different scenarios of how climate change will affect different parts of northern Europe are two direct results from the collaboration. 

NSC Directors during under 30 years. Patrick Norman, Anders Ynnerman, Sven Stafström, Bengt Persson, Larsgunnar Nilsson, Lars Eldén, Karl-Fredrik Berggren and Matts Karlsson.
Directors of NSC during its 30-year history. Patrick Norman, Anders Ynnerman, Sven Stafström, Bengt Persson, Larsgunnar Nilsson, Lars Eldén, Karl-Fredrik Berggren and Matts Karlsson.  Göran Billeson
Patrick Norman, Matts Karlsson and Niclas Andersson
Patrick Norman, Matts Karlsson and Niclas Andersson discuss petaflops and beyond. Göran Billeson
Guided tour in Kärnhuset
Peter Kjellström from NSC guides visitors around Kärnhuset. Göran Billeson
Celebration with cake
And a 30th birthday party must, of course, include a birthday cake. Göran Billeson
Matts Karlsson, Roar Skålin, Rolf Brennerfelt, Sven Stafström and Helen Dannetun
Matts Karlsson, Roar Skålin, Rolf Brennerfelt, Sven Stafström and Helen Dannetun cut the ribbon in unison. Göran Billeson


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