forked from lijiext/lammps
83 lines
2.4 KiB
Plaintext
83 lines
2.4 KiB
Plaintext
"Previous Section"_Section_packages.html - "LAMMPS WWW Site"_lws -
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"LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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"Return to Section accelerate overview"_Section_accelerate.html
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5.3.6 OPT package :h4
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The OPT package was developed by James Fischer (High Performance
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Technologies), David Richie, and Vincent Natoli (Stone Ridge
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Technologies). It contains a handful of pair styles whose compute()
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methods were rewritten in C++ templated form to reduce the overhead
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due to if tests and other conditional code.
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Here is a quick overview of how to use the OPT package:
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include the OPT package and build LAMMPS
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use OPT pair styles in your input script :ul
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The last step can be done using the "-sf opt" "command-line
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switch"_Section_start.html#start_7. Or the effect of the "-sf" switch
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can be duplicated by adding a "suffix opt"_suffix.html command to your
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input script.
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[Required hardware/software:]
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None.
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[Building LAMMPS with the OPT package:]
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Include the package and build LAMMPS:
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To do this in one line, use the src/Make.py script, described in
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"Section 2.4"_Section_start.html#start_4 of the manual. Type "Make.py
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-h" for help. If run from the src directory, this command will create
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src/lmp_opt using src/MAKE/Makefile.mpi as the starting
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Makefile.machine:
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Make.py -p opt -o opt -a file mpi :pre
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Or you can follow these steps:
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cd lammps/src
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make yes-opt
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make machine :pre
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If you are using Intel compilers, then the CCFLAGS setting in
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Makefile.machine needs to include "-restrict".
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[Run with the OPT package from the command line:]
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Use the "-sf opt" "command-line switch"_Section_start.html#start_7,
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which will automatically append "opt" to styles that support it.
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lmp_machine -sf opt -in in.script
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mpirun -np 4 lmp_machine -sf opt -in in.script :pre
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[Or run with the OPT package by editing an input script:]
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Use the "suffix opt"_suffix.html command, or you can explicitly add an
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"opt" suffix to individual styles in your input script, e.g.
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pair_style lj/cut/opt 2.5 :pre
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[Speed-ups to expect:]
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You should see a reduction in the "Pair time" value printed at the end
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of a run. On most machines for reasonable problem sizes, it will be a
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5 to 20% savings.
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[Guidelines for best performance:]
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None. Just try out an OPT pair style to see how it performs.
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[Restrictions:]
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None.
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