A supercomputer to map the cosmos

January 22, 2013

The ALMA correlator, one of the most powerful supercomputers in the world, has now been fully installed and tested at its remote, high altitude site in the Andes of northern Chile performing up to 17 quadrillion operations per second. (Credit: ESO)

A new petascale supercomputer built to study the universe is one of the fastest calculating machines in the world, and certainly the fastest of its kind.

The supercomputer is part of ALMA, a new radio telescope that is claimed to be “largest ground-based astronomical project in existence,” HPC Wire reports.

The ALMA (Atacama Large Millimeter/submillimeter Array and “soul” in Spanish) radio telescope is a collection of 66 high-precision antennas (parabolic dishes that act as receivers), strewn over the 5,000 meter-high Chajnantor desert plateau in northern Chile.

At those wavelengths, the antennas can detect the so-called “cool Universe,” molecular gas and dust as well as residual radiation from the Big Bang.

The antennas can be set to capture signals in a variety of configurations, such that the distance between them can vary between 150 meters to 16 kilometers. That gives the ALMA telescope something akin to a “zoom” capability, as well as very high sensitivity and resolution. As a result, it should be able to produce images 10 times sharper than that of the Hubble Space Telescope.

The challenge of multiple radio antennas is to make them behave as a single receiver, and for that you need some hefty number crunching — thus the need for a supercomputer. The one built for ALMA is actually a special-purpose device designed to correlate faint signals from multiple sources. Because of its function, the supercomputer is actually known as “the correlator.”

The correlator delivers 17 quadrillion operations per second. That’s 17 petaOPS (not petaFLOPS). If you discount these are not floating point operations, the system operates at a level comparable to Titan, the fastest general-purpose supercomputer in the world, and the current title-holder on the TOP500.

Because it is purpose-built for these correlation functions, the silicon is able to deliver 512 billion operations per second (gigaOPS).

There are also 17 ancillary computers involved in acquiring and calibrating data from the correlator hardware. The correlator itself is designed to receive 96 gigabits per second from up to 64 antennas and can sustain an output rate of 1 gigabyte per second.

The international project is slated to be completely operational in March 2013. It includes partners from Europe (European Southern Observatory, Laboratoire d’Astrophysique de Bordeaux), North America (National Radio Astronomy Observatory), and Japan (National Astronomical Observatory of Japan). The Joint ALMA Observatory, based in Santiago Chile, manages the project.