Supercomputers making our future
When the Tianhe-1 supercomputer was ranked No 1 in the world last year, it suddenly and greatly raised the profile of supercomputing in China. This year, with the announcement of the Sunway Blue Light, which uses domestic processors, in Jinan, there are three petaflop-level supercomputers in China including Tianhe-1 in Tianjin and Nebulae in Shenzhen. It is clear that China's computer science and computational science is making great progress.
For most people, supercomputers have an air of mystery, yet such computers have a close bearing on many people's lives. Many fields demand the help of supercomputers. A simple definition of supercomputer is "computers connected by a network". These computers, called nodes, could be personal desktop computers, servers, workstations, and even notebooks. The network connecting these nodes could be an Ethernet, a high-speed network or some specially designed network. Usually when people talk about supercomputers they are referring to the system with many high-performance nodes, a high-speed network, large memory and disk space so that the system has large processing capacity and high computational speed.
Another expression closely related to supercomputing is parallel computation. In normal computers, most programs run sequentially. For sequential programs, supercomputers offer no significant advantage over normal computers. However, for parallel programs or parallel tasks, the computing nodes in supercomputers can work together by using many processors and exchange information through a high-speed network. That means computation can be sped up.
Supercomputers are widely used in scientific research, industrial engineering, information processing, finance and public affairs. They have become one of the most important tools in research and innovation, greatly speeding up research and development and improving product competitiveness. In basic scientific research, a lot of physical or chemical behavior can be observed through experiments, but only at considerable cost. Supercomputers offer the possibility of simulating such behavior so that it can be more easily studied and better understood. In astrophysics and environmental science, people use Newtonian mechanics to simulate large-scale phenomena such as the evolution of galaxies, climate change, and ocean circulation.
In micro fields, quantum mechanics and molecular dynamic methods are used to stimulate atomic or molecular behavior such as protein folding, gene sequencing, nano materials and devices, catalytic processes, and chemical reaction processes. Indeed, the demand for computing capacity is endless in basic research fields. For example, at the Shanghai Supercomputer Center, which has the broadest and most successful supercomputer applications in China, almost 80 percent of computing resources are used in basic scientific research. In industrial engineering fields, supercomputing is mainly used in computer aided engineering (CAE). By using CAE, the product development cycle and cost are reduced greatly, and product competitiveness is improved significantly.
In aviation, people use supercomputers to carry out aerodynamic design and large-scale, detailed and precise computational fluid dynamics (CFD) simulation. In the design and development of China's first new regional jet the ARJ21-700, the Shanghai center's supercomputer was used to finish the design requirements determination, preliminary conceptual design and detailed design. During the conceptual design stage and the preliminary design stage of the ARJ, CFD analysis was made to reduce the number of wind tunnel tests and comply with fast and highly iterative engineering design. During the detailed-design stage, CFD analysis and design optimization were made for various components and component combinations, for instance, aerodynamic shape and design optimization of airfoil, wing, nose, tail, nacelle and pylon. In one project now being carried out on the China-made large passenger aircraft C919, the Shanghai supercomputer has been used for configuration design and aerodynamic design, which includes the nose, wings, wingtip, nacelle, and body design optimization.
In the automobile industry, the supercomputer can be used for finite element analysis and structure analysis. In car design, passive safety is very important. In the research and development of vehicles, the virtual crash analysis of safety design can be done on a supercomputer. With such computing resources, whether it be the number of virtual crash tests, analysis accuracy, analysis precision or design cycle, we move close to the world's leading automotive research and development levels. Thus, the passive safety performance of vehicles can reach the highest level, and the product development cycle is shortened and development costs are reduced. In other areas of vehicle design, structural analysis using supercomputers is also widely used, such as in sub-frame design, developing new child safety seats, and durability analysis.
In the marine industry, CFD simulation on a supercomputer is an important research and development tool. In modern shipbuilding, CFD technology on supercomputers is used to inspect flow phenomena and principles of the multi-propeller propulsion system, provide details on the performance and mechanism of such a system, improve designers' awareness of performance, and provide a technical consulting service for related development and designs.
In the iron and steel industry, numerical simulation on supercomputers is used to improve equipment and production. For example, a simulation of steel flow, solidification and temperature distribution in molds was used to analyze how different entry nozzles, sections and drawing speed affect the flow field, temperature field and the thickness of solidified matter.
In civil engineering, large-scale numerical simulation on a supercomputer can be helpful for building tunnels, bridges, large-scale building and so on. In the building of the Shanghai Yangzi tunnel, numerical simulation based on the Shanghai supercomputer helped solve problems that were the product of complicated geological and environmental conditions. Vibration analysis was also done on the supercomputer.
As supercomputers have become more and more important in people's lives over the past 10 years, China has made great efforts in their development.
From the 4000A supercomputer (ranked 10th in the world in 2004), Magic Cube (ranked first in Asia in 2008), to Tianhe-1A (first in the world last year), China's domestic supercomputer has made remarkable progress.
Computation capability and capacity has undergone tremendous growth. Up to last month China's supercomputer system number ranked second in the top 500 fastest supercomputers in the world, and total computation capacity ranked 3rd. However, even though supercomputer hardware has developed greatly, software and operations lag behind those of major Western countries. Most computation software packages running on domestic supercomputers are foreign.
In scalability, stability, functionality, acceptability and computational efficiency, domestic parallel computational software lags far behind its foreign counterparts. In operations, China still lacks a long-term plan or project and effective policy to support the development of a supercomputer center, which does nothing to help the long-term development of China's supercomputer.
The author is the manager and chief scientific computing engineer at the department of HPC Application Technology, Shanghai Supercomputer Center.
