2006-09-22 00:22:34 +08:00
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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<HR>
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<H3>create_box command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>create_box N region-ID
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</PRE>
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<UL><LI>N = # of atom types to use in this simulation
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<LI>region-ID = ID of region to use as simulation domain
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</UL>
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<P><B>Examples:</B>
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</P>
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2007-03-22 23:37:43 +08:00
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<PRE>create_box 2 mybox
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2006-09-22 00:22:34 +08:00
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</PRE>
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<P><B>Description:</B>
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</P>
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2007-03-08 09:01:08 +08:00
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<P>This command creates a simulation box based on the specified region.
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Thus a <A HREF = "region.html">region</A> command must first be used to define a
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geometric domain.
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2006-09-22 00:22:34 +08:00
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</P>
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<P>The argument N is the number of atom types that will be used in the
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simulation.
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</P>
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2007-03-08 09:01:08 +08:00
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<P>If the region is not of style <I>prism</I>, then LAMMPS encloses the region
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(block, sphere, etc) with an axis-aligned (orthogonal) box which
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becomes the simulation domain.
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</P>
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<P>If the region is of style <I>prism</I>, LAMMPS creates a non-orthogonal
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simulation domain shaped as a parallelepiped with triclinic symmetry.
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See the <A HREF = "region.html">region prism</A> command for a description of how
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the shape of the parallelepiped is defined. The parallelepiped has
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its "origin" at (xlo,ylo,zlo) and 3 edge vectors starting from its
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origin given by a = (xhi-xlo,0,0); b = (xy,yhi-ylo,0); c =
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(xz,yz,zhi-zlo).
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</P>
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2007-04-02 22:26:01 +08:00
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<P>A prism region used with the create_box command must have tilt factors
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(xy,xz,yz) that do not skew the box more than half the distance of the
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2007-06-20 20:56:17 +08:00
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parallel box length. For example, if xlo = 2 and xhi = 12, then the x
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box length is 10 and the xy tilt factor must be between -5 and 5.
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Similarly, both xz and yz must be between -(xhi-xlo)/2 and
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+(yhi-ylo)/2. Note that this is not a limitation, since if the
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maximum tilt factor is 5 (as in this example), then configurations
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with tilt = ..., -15, -5, 5, 15, 25, ... are all equivalent.
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2007-03-08 09:01:08 +08:00
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</P>
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<P>When a prism region is used, the simulation domain must be periodic in
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2007-04-02 22:26:01 +08:00
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any dimensions with a non-zero tilt factor, as defined by the
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<A HREF = "boundary.html">boundary</A> command. I.e. if the xy tilt factor is
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non-zero, then both the x and y dimensions must be periodic.
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Similarly, x and z must be periodic if xz is non-zero and y and z must
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be periodic if yz is non-zero.
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2007-03-08 09:01:08 +08:00
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</P>
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2006-09-22 00:22:34 +08:00
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<P><B>Restrictions:</B>
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</P>
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<P>An <A HREF = "atom_style.html">atom_style</A> and <A HREF = "region.html">region</A> must have
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been previously defined to use this command.
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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 = "create_atoms.html">create_atoms</A>, <A HREF = "region.html">region</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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