Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

TENDL: complete nuclear data library for innovative nuclear science and technology

The joint evaluated fission and fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides $^{235}\hbox {U}$, $^{238}\hbox {U}$ and $^{239}\hbox {Pu}$, on $^{241}\hbox {Am}$ and $^{23}\hbox {Na}$, $^{59}\hbox {Ni}$, Cr, Cu, Zr, Cd, Hf, W, Au, Pb and Bi are presented. It includes new fission yields, prompt fission neutron spectra and average number of neutrons per fission. In addition, new data for radioactive decay, thermal neutron scattering, gamma-ray emission, neutron activation, delayed neutrons and displacement damage are presented. JEFF-3.3 was complemented by files from the TENDL project. The libraries for photon, proton, deuteron, triton, helion and alpha-particle induced reactions are from TENDL-2017. The demands for uncertainty quantification in modeling led to many new covariance data for the evaluations. A comparison between results from model calculations using the JEFF-3.3 library and those from benchmark experiments for criticality, delayed neutron yields, shielding and decay heat, reveals that JEFF-3.3 performes very well for a wide range of nuclear technology applications, in particular nuclear energy.

/pdf/the-joint-evaluated-fission-and-fusion-nuclear-data-library-3xawwctw8e.pdf

The joint evaluated fission and fusion nuclear data library, JEFF-3.3

https://openresearch-repository.anu.edu.au/bitstream/1885/199602/2/01_Carlson_Evaluation_of_the_Neutron_Data_2018.pdf

Evaluation of the Neutron Data Standards

Neutron Cross Sections Prepared by the United States Atomic Energy Commission (Selected Reference Material on Atomic Energy) Pp viii + 328 (London: McGraw-Hill Publishing Company, Ltd, 1955) 90s

/pdf/neutron-cross-sections-1bmmld6x38.pdf

Neutron Cross-Sections

https://escholarship.org/content/qt2dj9p3h4/qt2dj9p3h4.pdf?t=pmi3bw

E.S. Soukhovitskii

Papers

ENDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data