diff --git a/bench/README b/bench/README new file mode 100644 index 0000000000000000000000000000000000000000..964196d19972a5cb791b37bbd661de88c96d54b5 --- /dev/null +++ b/bench/README @@ -0,0 +1,100 @@ +LAMMPS benchmark problems + +This directory contains 5 benchmark problems which are discussed in +the Benchmark section of the LAMMPS documentation. + +Each of the 5 problems has 32,000 atoms and runs for 100 timesteps. +Each can be run as a serial benchmark (on one processor) or in +parallel. In parallel, each benchmark can be run as a fixed-size or +scaled-size problem. For fixed-size benchmarking, the same 32K atom +problem is run on various numbers of processors. For scaled-size +benchmarking, the model size is increased with the number of +processors. E.g. on 8 processors, a 256K-atom problem is run; on 1024 +processors, a 32-million atom problem is run, etc. + +A few sample log file outputs on different machines and different +numbers of processors are included in this directory to compare your +answers to. E.g. a log file like log.date.chain.lmp.scaled.foo.P is +for a scaled-size version of the Chain benchmark, run on P processors +of machine "foo" with the dated version of LAMMPS. Note that the Eam +and Lj benchmarks may not give identical answers on different machines +because of the "velocity loop geom" option that assigns velocities +based on atom coordinates - see the discussion in the documentation +for the velocity command for details. + +The CPU time (in seconds) for the run is in the "Loop time" line +of the log files, e.g. + +Loop time of 3.89418 on 8 procs for 100 steps with 32000 atoms + +Timing results for these problems run on various machines are listed +on the Benchmarks page of the LAMMPS WWW Site. + +---------------------------------------------------------------------- + +These are the 5 benchmark problems: + +LJ = atomic fluid, Lennard-Jones potential with 2.5 sigma cutoff (55 +neighbors per atom), NVE integration + +Chain = bead-spring polymer melt of 100-mer chains, FENE bonds and LJ +pairwise interactions with a 2^(1/6) sigma cutoff (5 neighbors per +atom), NVE integration + +EAM = metallic solid, Cu EAM potential with 4.95 Angstrom cutoff (45 +neighbors per atom), NVE integration + +Chute = granular chute flow, frictional history potential with 1.1 +sigma cutoff (7 neighbors per atom), NVE integration + +Rhodo = rhodopsin protein in solvated lipid bilayer, CHARMM force +field with a 10 Angstrom LJ cutoff (440 neighbors per atom), +particle-particle particle-mesh (PPPM) for long-range Coulombics, NPT +integration + +---------------------------------------------------------------------- + +Here is how to run each problem, assuming the LAMMPS executable is +named lmp_foo, and you are using the mpirun command to launch parallel +runs: + +Serial (one processor runs): + +lmp_foo < in.lj +lmp_foo < in.chain +lmp_foo < in.eam +lmp_foo < in.chute +lmp_foo < in.rhodo + +Parallel fixed-size runs (on 8 procs in this case): + +mpirun -np 8 lmp_foo < in.lj +mpirun -np 8 lmp_foo < in.chain +mpirun -np 8 lmp_foo < in.eam +mpirun -np 8 lmp_foo < in.chute +mpirun -np 8 lmp_foo < in.rhodo + +Parallel scaled-size runs (on 16 procs in this case): + +mpirun -np 16 lmp_foo -var x 40 -var y 40 -var z 80 < in.lj +mpirun -np 16 lmp_foo -var x 2 -var y 2 -var z 4 < in.chain.scaled +mpirun -np 16 lmp_foo -var x 40 -var y 40 -var z 80 < in.eam +mpirun -np 16 lmp_foo -var x 4 -var y 4 < in.chute.scaled +mpirun -np 16 lmp_foo -var x 2 -var y 2 -var z 4 <