Nuclear weapon simulations calculate in molecular detail

U.S. researchers at Purdue University and NNSA's Lawrence Livermore National Laboratory are perfecting simulations that show a nuclear weapon's performance in precise molecular detail. These tools are becoming critical for national defense due to international treaties forbidding the detonation of nuclear test weapons.The simulations are required to operate on supercomputers containing thousands of processors, but doing so has posed reliability and accuracy problems. Each machine in the supercomputer cluster contains several cores. The researchers created an automated method for grouping the large number of processes into a smaller number of "equivalence classes" with similar traits. Grouping the processes into equivalence classes makes it possible to quickly detect and pinpoint problems.