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Primeur weekly 2013-08-19

Special

Is 64-bit arithmetic likely to become essential in future scientific computing? ...

Focus

EGI.eu and the University of Messina provided training on Europe's largest scientific federated Cloud at the Cloud Summerschool Almere ...

The Cloud

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GAME wins customer loyalty through a Cloud based, IBM smarter commerce approach ...

IBM awarded 10 year $1 billion Cloud hosting services contract to assist US Department of Interior's move to Cloud computing ...

Desktop Grids

.NET GUI RPC binding available ...

EuroFlash

Keynote speakers announced for Altair's Biennial Technology Conference ...

Using high-performance computing to gain new insights into turbulence ...

PRACE to issue Open Calls for Proposals for Regular Access ...

A significant EU supercomputing resource for simulations of interactions between enteroviruses and gold nanoparticles ...

Deutsches Krebsforschungszentrum installs Convey hybrid-core computers to speed next-generation sequencing ...

Teleported by electronic circuit: ETH-physicists beam information ...

Quantum teleportation: Transfer of flying quantum bits at the touch of a button ...

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GE and Sandia National Lab discover pathway to quieter, more productive wind turbines ...

Western Australian Government invests $26 million in astronomy and the Square Kilometre Array ...

Researchers at Michigan State University use TACC supercomputers to understand DNA bending and repair mechanisms ...

Themis Systems introduces NVIDIA Kepler-based GPGPU and NVIDIA GRID accelerated RES-NT2 high performance computers ...

HP helps software-defined storage customers maximize server investments with data tiering ...

IBM to acquire Trusteer to help companies combat financial fraud and advanced security threats ...

Oracle introduces the Oracle Virtual Compute Appliance ...

Memory breakthrough could bring faster computing, smaller memory devices and lower power consumption ...

SMART Modular Technologies announces new e.MMC product family ...

Scientists find asymmetry in topological insulators ...

Is 64-bit arithmetic likely to become essential in future scientific computing?


20 Jun 2013 Leipzig - In the session on "High-End systems towards Exascale" at the ISC'13 event in Leipzig, David H. Bailey from Lawrence Berkeley National Laboratory talked about numerical reproducibility in exascale computing. He seemed convinced that the use of 64-bit arithmetic might become essential for future scientific computing.

David Bailey stated that science is built upon the foundations of theory and experiment validated and improved through open and transparent communication. Numerical round-off error and numerical differences though are greatly magnified as computational simulations are scaled up to run on highly parallel systems.

The problem of numerical reliability is that many applications routinely use either 32-bit or 64-bit IEEE arithmetic.

The 2012 discovery of the Higgs boson in the ATLAS experiment at the Large Hadron Collider in Geneva relied crucially on the ability to track charged particles with an exquisite precision and high reliability, David Bailey explained

The software involved 5 millions line of C++ and python code, developed by roughly 2000 physicists and engineers over 15 years.

Recently, in an attempt to speed up the calculation, one has employed expert numerical analysts to re-examine every algorithm employed in the computation to ensure that only the most stable known schemes are being used, as the speaker outlined.

Of the 2010 University of California at Berkeley graduation class, 870 students were in a discipline likely to require technical computing. Fewer than 2% of Berkeley graduates who will do technical computing have had rigorous training in numerical analysis. David Bailey thought this might become problematic for future HPC development.

Plans are being unfolded to enhance reproducibility with high-precision arithmetic. The computation takes only 3.47 seconds when the summation is changed to double-double, the result is identical to the double-double result.

There has been considerable resistance in the scientific computing community to the notion that more than 64-bit arithmetic is not only useful, but may even be essential in some scientific computing.

David Bailey expanded on the CORVETTE project and the Precimonious tool. The aim is to develop software facilities to find and ameliorate numerical anomalies in large-scale computations. This involves facilities to test the level of numerical accuracy rewired for an application; facilities to delimit the portions of code that are inaccurate; facilities to search the space of possible code modifications; and facilities to repair numerical difficulties including usage of high precision arithmetic.

David Bailey said that applications where high precision is useful or essential are planetary orbit calculations but also supernova simulations. Researchers at Lawrence Berkeley National Laboratory have used quad-double arithmetic to solve for non-local thermodynamic equilibrium.

In climate modelling, computational results are altered even if minor changes are made to the code or the system. Numerical variation is a major nuisance for code maintenance, David Bailey explained. By using double-double arithmetic in two key inner loops, most of this numerical variation disappeared.

The most practical solution to difficulties is to judiciously employ higher-precision arithmetic, combined with some smart tools to identify sensitivities and make the requisite code modifications, David Bailey stated.

Fortunately, such computations are now feasible using modern HPC technology, he concluded.
Leslie Versweyveld

Back to Table of contents

Primeur weekly 2013-08-19

Special

Is 64-bit arithmetic likely to become essential in future scientific computing? ...

Focus

EGI.eu and the University of Messina provided training on Europe's largest scientific federated Cloud at the Cloud Summerschool Almere ...

The Cloud

On our Way towards a New Utility ...

Distributed data safer than centralized Cloud data ...

South Africa's National Airways Corporation securing 20 terabytes of data in HP Autonomy Cloud ...

GAME wins customer loyalty through a Cloud based, IBM smarter commerce approach ...

IBM awarded 10 year $1 billion Cloud hosting services contract to assist US Department of Interior's move to Cloud computing ...

Desktop Grids

.NET GUI RPC binding available ...

EuroFlash

Keynote speakers announced for Altair's Biennial Technology Conference ...

Using high-performance computing to gain new insights into turbulence ...

PRACE to issue Open Calls for Proposals for Regular Access ...

A significant EU supercomputing resource for simulations of interactions between enteroviruses and gold nanoparticles ...

Deutsches Krebsforschungszentrum installs Convey hybrid-core computers to speed next-generation sequencing ...

Teleported by electronic circuit: ETH-physicists beam information ...

Quantum teleportation: Transfer of flying quantum bits at the touch of a button ...

USFlash

GE and Sandia National Lab discover pathway to quieter, more productive wind turbines ...

Western Australian Government invests $26 million in astronomy and the Square Kilometre Array ...

Researchers at Michigan State University use TACC supercomputers to understand DNA bending and repair mechanisms ...

Themis Systems introduces NVIDIA Kepler-based GPGPU and NVIDIA GRID accelerated RES-NT2 high performance computers ...

HP helps software-defined storage customers maximize server investments with data tiering ...

IBM to acquire Trusteer to help companies combat financial fraud and advanced security threats ...

Oracle introduces the Oracle Virtual Compute Appliance ...

Memory breakthrough could bring faster computing, smaller memory devices and lower power consumption ...

SMART Modular Technologies announces new e.MMC product family ...

Scientists find asymmetry in topological insulators ...