Create an arbitrarily oriented straight dislocation line.

<p>
Usage: <tt>input = [ <i>enable a bx by bz lx ly lz nx ny nz x0 y0 z0 nu store</i> ] 
       makedislocation</tt>

<p>
<p>
<tt><i>enable = 1</i></tt> activates this command.  <br>
<tt><i>a</i></tt> is a length scale (in &Aring;) for the Burgers vector.<br>
<tt><i>bx, by, bz</i></tt> is the Burgers vector (in real coordinates) in unit of 
  <tt><i>a</i></tt>.<br>
<tt><i>lx, ly, lz</i></tt> is the dislocation line orientation (in real coordinates).<br>
<tt><i>nx, ny, nz</i></tt> is the normal vector (in real coordinates) of the cut plane.<br>
<tt><i>x0, y0, z0</i></tt> is a point on the cut-plane.<br>
<tt><i>nu</i></tt> is the Poisson's ratio of the crystal, needed in the expression 
 for the displacement field of non-screw dislocations. <tt><i>nu</i></tt> is usually set to be 0.3.
<br>
If <tt><i>store</i> = 1</tt>, the displacement field is not committed to the atoms
positions, but is stored/accumulated in array <tt>storedr</tt>, until this command is
(or other commands such as <tt>makedipole</tt>) is called again with option 
<tt><i>store</i> = 0</tt>.

<p>
Note: vectors <b>b</b>, <b>l</b>, <b>n</b> are all expressed in the lab coordinate system,
not the crystal coordinate system.

<p>
Note: This cannot work if the simulation cell is subjected to periodic boundary
condition (PBC) in all three directions.  Use <tt>makedipole</tt> instead
in such conditions.

<p>
Also see <tt>makecylinder</tt>.

<p>
Example: <tt>MD++/scripts/CSD-book/chap3/sect3.1/ta-screw.script</tt>

<p>
For details, see <a href="http://micro.stanford.edu/~caiwei/CSD-Book/">Computer Simulations
of Dislocations</a>, Chapter 3, Section 3.1.

