2016-05-10 01:33:12 +08:00
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< li class = "toctree-l1" > < a class = "reference internal" href = "Section_intro.html" > 1. Introduction< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "Section_accelerate.html" > 5. Accelerating LAMMPS performance< / a > < / li >
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< li > dihedral_style quadratic command< / li >
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< a href = "Section_commands.html#comm" > Commands< / a >
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< div class = "section" id = "dihedral-style-quadratic-command" >
< span id = "index-0" > < / span > < h1 > dihedral_style quadratic command< / h1 >
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< div class = "section" id = "dihedral-style-quadratic-omp-command" >
< h1 > dihedral_style quadratic/omp command< / h1 >
< div class = "section" id = "syntax" >
< h2 > Syntax< / h2 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > dihedral_style< / span > < span class = "n" > quadratic< / span >
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< h2 > Examples< / h2 >
< div class = "highlight-default" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > dihedral_style< / span > < span class = "n" > quadratic< / span >
< span class = "n" > dihedral_coeff< / span > < span class = "mf" > 100.0< / span > < span class = "mf" > 80.0< / span >
< / pre > < / div >
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< h2 > Description< / h2 >
< p > The < em > quadratic< / em > dihedral style uses the potential:< / p >
< img alt = "_images/dihedral_quadratic.jpg" class = "align-center" src = "_images/dihedral_quadratic.jpg" / >
< p > This dihedral potential can be used to keep a dihedral in a predefined
value (cis=zero, right-hand convention is used).< / p >
< p > The following coefficients must be defined for each dihedral type via
the < a class = "reference internal" href = "dihedral_coeff.html" > < span class = "doc" > dihedral_coeff< / span > < / a > command as in the example
above, or in the data file or restart files read by the
< a class = "reference internal" href = "read_data.html" > < span class = "doc" > read_data< / span > < / a > or < a class = "reference internal" href = "read_restart.html" > < span class = "doc" > read_restart< / span > < / a >
commands:< / p >
< ul class = "simple" >
< li > K (energy/radian^2)< / li >
< li > phi0 (degrees)< / li >
< / ul >
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< p > Styles with a < em > gpu< / em > , < em > intel< / em > , < em > kk< / em > , < em > omp< / em > , or < em > opt< / em > suffix are
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functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in < a class = "reference internal" href = "Section_accelerate.html" > < span class = "doc" > Section_accelerate< / span > < / a >
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.< / p >
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< p > These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
USER-OMP and OPT packages, respectively. They are only enabled if
LAMMPS was built with those packages. See the < a class = "reference internal" href = "Section_start.html#start-3" > < span class = "std std-ref" > Making LAMMPS< / span > < / a > section for more info.< / p >
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< p > You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the < a class = "reference internal" href = "Section_start.html#start-7" > < span class = "std std-ref" > -suffix command-line switch< / span > < / a > when you invoke LAMMPS, or you can
use the < a class = "reference internal" href = "suffix.html" > < span class = "doc" > suffix< / span > < / a > command in your input script.< / p >
< p > See < a class = "reference internal" href = "Section_accelerate.html" > < span class = "doc" > Section_accelerate< / span > < / a > of the manual for
more instructions on how to use the accelerated styles effectively.< / p >
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< div class = "section" id = "restrictions" >
< h2 > Restrictions< / h2 >
< p > This angle style can only be used if LAMMPS was built with the
USER_MISC package. See the < a class = "reference internal" href = "Section_start.html#start-3" > < span class = "std std-ref" > Making LAMMPS< / span > < / a >
section for more info on packages.< / p >
< / div >
< div class = "section" id = "related-commands" >
< h2 > Related commands< / h2 >
< p > < a class = "reference internal" href = "dihedral_coeff.html" > < span class = "doc" > dihedral_coeff< / span > < / a > < / p >
< p > < strong > Default:< / strong > none< / p >
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