118 lines
4.4 KiB
HTML
118 lines
4.4 KiB
HTML
<HTML>
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<CENTER><A HREF = "http://www.cfdem.com">LIGGGHTS WWW Site</A> - <A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LIGGGHTS Documentation</A> - <A HREF = "Section_commands.html#comm">LIGGGHTS Commands</A>
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</CENTER>
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<HR>
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<H3>fix property/global command
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</H3>
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<H3>fix property/atom command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>fix id group property/atom variablename style restartvalue comm_ghost_value comm_reverse_ghost_value defaultvalue(s)...
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fix id group property/global variablename style stylearg defaultvalue(s)...
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</PRE>
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<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command
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<LI>property/global or property/atom = style name of this fix command
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<LI>variablename = a valid C++ string
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<LI>restartvalues = 'yes' or 'no'
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<LI>comm_ghost_value = 'yes' or 'no'
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<LI>comm_reverse_ghost_value = 'yes' or 'no'
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</UL>
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<P>fix property/global:
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</P>
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<UL><LI> style = scalar or vector or atomtype or matrix or atomtypepair
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<PRE> stylearg for scalar/vector: none
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stylearg for matrix/atomtypepair: nCols
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</PRE>
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</UL>
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<P>fix property/atom:
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</P>
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<UL><LI> style = scalar or vector
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<LI> restartvalue = yes or no
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<LI> communicate_ghost_value = yes or no
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<LI> communicate_reverse_ghost_value = yes or no
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>fix m3 all property/global coefficientRestitution peratomtypepair 1 0.3
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fix m5 all property/global characteristicVelocity scalar 2.
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fix uf all property/atom uf vector yes no no 0. 0. 0.
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</PRE>
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<P><B>LIGGGHTS vs. LAMMPS Info:</B>
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</P>
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<P>This LIGGGHTS command is not available in LAMMPS.
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</P>
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<P><B>Description:</B>
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</P>
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<P><B>Fix property/atom</B> reserves per-atom properties to be accessed by the user or other fixes.
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Style <I>scalar</I> reserves one value per atom, style <I>vector</I> multiple values per atoms, where
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the number of <I>defaultvalues</I> (that are assigned to the atoms at creation) determines the
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length of the vector. The group of atoms the fix is applied to is always "all", irrespective
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of which group is used for the fix command . If you want to assign different values for
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different groups, you can use the <A HREF = "set.html">set</A> command with keyword 'property/atom'.
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Keyword <I>restartvalues</I> determines whether information about the values stored by this fix
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is written to binary restart files.
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Keyword <I>communicate_ghost_value</I> determines whether information about the values stored by this fix
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can be communicated to ghost particles (forward communication). The exact location during a time-step
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when this happens depends on the model that uses this fix.
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Keyword <I>communicate_reverse_ghost_value</I> determines whether information about the values stored by this fix
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can be communicated from ghost particles to owned particles (reverse communication). The exact location
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during a time-step when this happens depends on the model that uses this fix.
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</P>
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<P><B>Fix property/global</B> reserves global properties to be accessed by the user or other
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fixes or pair styles. The number of defaultvalues determines the length of the vector /
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the number of matrix components . For style <I>vector</I> or <I>atomtype</I>, the user provides
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the number of vector components . For style <I>matrix</I> or <I>atomtypepair</I>, the user provides
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the number of matrix columns (<I>nCols</I>) .
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</P>
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<P>Example: <I>nCols</I>= 2 and <I>defaultvalues</I> = 1 2 3 4 5 6 would be mapped into a matrix like
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</P>
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<P>[ 1 2 ]
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</P>
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<P>[ 3 4 ]
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</P>
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<P>[ 5 6 ]
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</P>
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<P>Note that the number of default values must thus be a multiple of <I>nCols</I>.
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Note that <I>vector</I> and <I>atomtype</I> do the same thing, <I>atomtype</I> is just provided to make input scripts more readable .
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Note that <I>matrix</I> and <I>atomtypepair</I> both refer to a matrix of global values. However, a matrix defined via <I>atomtypepair</I> is required to be symmetric.
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</P>
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<P>Note that the group of atoms the fix is applied to is ignored (as the fix is not applied to atoms, but defines values of global scope).
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</P>
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<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
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</P>
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<P>Information about this fix is written to <A HREF = "restart.html">binary restart files</A> if you set <I>restartvalue</I> to 'yes'.
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</P>
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<P><B>Restrictions:</B> none
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "set.html">set</A>, <A HREF = "pair_gran.html">pair_gran</A>
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</P>
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<P><B>Default:</B> none
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</P>
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</HTML>
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