From http://www.nersc.gov/news/newNERSCresults050703.pdf:

Terascale Simulations of Supernovae
In the terascale simulations of supernovae, OAK3D is a code which tackles the quantum mechanical many-body theory of the structure of nuclei to determine how neutrinos scatter on lattices. It is a parallel, 3D coordinate space, fully time-dependent Hartree-Fock code with realistic (Skyrme) nuclear forces. Mathematically the effort reduces this problem to an iteration over dense complex nonsymmetric linear system solutions coupled with matrix-vector operations to impose time evolution. Several routines from the ScaLAPACK and PBLAS libraries are used to perform this task. Matrix factorizations are performed using PZGETRF, and the triangular solutions are carried out using PZTRSM. The size of the linear systems being solved is determined by the method of discretizing the equations. For a 48 × 48 × 48 space lattice, the size of the matrix is 221,184. Approximately 90% of the computing time on a typical run is spent solving the linear systems. On 2,048 processors of Seaborg, OAK3D took six hours to compute a full iteration at a sustained rate of about 43% of peak.

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