Merge branch 'master' into tokenizer-performance-fixes

         radius = cylinder radius (distance units)

* zero or more keyword/value pairs may be appended to args

* keyword = *wiggle* or *shear*

* keyword = *wiggle* or *shear* or *contacts*

  .. parsed-literal::

       *shear* values = dim vshear

         dim = *x* or *y* or *z*

         vshear = magnitude of shear velocity (velocity units)

      *contacts* value = none

         generate contact information for each particle

Examples

""""""""

   fix 3 all wall/gran/region granular hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 damping velocity region myBox

   fix 4 all wall/gran/region granular jkr 1e5 1500.0 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall region myCone

   fix 5 all wall/gran/region granular dmt 1e5 0.2 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall damping tsuji region myCone

   fix 6 all wall/gran hooke  200000.0 NULL 50.0 NULL 0.5 0 xplane -10.0 10.0 contacts

Description

"""""""""""

*vshear* < 0.  In this case, *vshear* is the tangential velocity of

the wall at whatever *radius* has been defined.

**Restart, fix_modify, output, run start/stop, minimize info:**

This fix writes the shear friction state of atoms interacting with the

restart file, so that the operation of the fix continues in an

uninterrupted fashion.

None of the :doc:`fix_modify <fix_modify>` options are relevant to this

fix.  No global or per-atom quantities are stored by this fix for

access by various :doc:`output commands <Howto_output>`.  No parameter

of this fix can be used with the *start/stop* keywords of the

:doc:`run <run>` command.  This fix is not invoked during :doc:`energy minimization <minimize>`.

If the :code:`contacts` option is used, this fix generates a per-atom array

with 8 columns as output, containing the contact information for owned

particles (nlocal on each processor). All columns in this per-atom array will

be zero if no contact has occurred.  The values of these columns are listed in

the following table:

+-------+----------------------------------------------------+----------------+

| Index | Value                                              | Units          |

+=======+====================================================+================+

|     1 | 1.0 if particle is in contact with wall,           |                |

|       | 0.0 otherwise                                      |                |

+-------+----------------------------------------------------+----------------+

|     2 | Force :math:`f_x` exerted on the wall              | force units    |

+-------+----------------------------------------------------+----------------+

|     3 | Force :math:`f_y` exerted on the wall              | force units    |

+-------+----------------------------------------------------+----------------+

|     4 | Force :math:`f_z` exerted on the wall              | force units    |

+-------+----------------------------------------------------+----------------+

|     5 | :math:`\Delta x` between wall surface and particle | distance units |

+-------+----------------------------------------------------+----------------+

|     6 | :math:`\Delta y` between wall surface and particle | distance units |

+-------+----------------------------------------------------+----------------+

|     7 | :math:`\Delta z` between wall surface and particle | distance units |

+-------+----------------------------------------------------+----------------+

|     8 | Radius :math:`r` of atom                           | distance units |

+-------+----------------------------------------------------+----------------+

None of the :doc:`fix_modify <fix_modify>` options are relevant to this fix.

No parameter of this fix can be used with the *start/stop* keywords of the

:doc:`run <run>` command. This fix is not invoked during :doc:`energy

minimization <minimize>`.

Restrictions

""""""""""""

.. parsed-literal::

   fix ID group-ID wall/gran/region fstyle fstyle_params wallstyle regionID

   fix ID group-ID wall/gran/region fstyle fstyle_params wallstyle regionID keyword values ...

* ID, group-ID are documented in :doc:`fix <fix>` command

* wall/region = style name of this fix command

* wallstyle = region (see :doc:`fix wall/gran <fix_wall_gran>` for options for other kinds of walls)

* region-ID = region whose boundary will act as wall

* keyword = *contacts*

  .. parsed-literal::

      *contacts* value = none

         generate contact information for each particle

Examples

""""""""

   fix 3 all wall/gran/region granular hooke 1000.0 50.0 tangential linear_nohistory 1.0 0.4 damping velocity region myBox

   fix 4 all wall/gran/region granular jkr 1e5 1500.0 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall region myCone

   fix 5 all wall/gran/region granular dmt 1e5 0.2 0.3 10.0 tangential mindlin NULL 1.0 0.5 rolling sds 500.0 200.0 0.5 twisting marshall damping tsuji region myCone

   fix wall all wall/gran/region hooke/history 1000.0 200.0 200.0 100.0 0.5 1 region myCone contacts

Description

"""""""""""

   use the same fix ID for fix wall/gran/region, but assign it a region

   with a different region ID.

None of the :doc:`fix_modify <fix_modify>` options are relevant to this

fix.  No global or per-atom quantities are stored by this fix for

access by various :doc:`output commands <Howto_output>`.  No parameter

of this fix can be used with the *start/stop* keywords of the

:doc:`run <run>` command.  This fix is not invoked during :doc:`energy minimization <minimize>`.

If the :code:`contacts` option is used, this fix generates a per-atom array

with 8 columns as output, containing the contact information for owned

particles (nlocal on each processor). All columns in this per-atom array will

be zero if no contact has occurred. The values of these columns are listed in

the following table:

+-------+----------------------------------------------------+----------------+

| Index | Value                                              | Units          |

+=======+====================================================+================+

|     1 | 1.0 if particle is in contact with wall,           |                |

|       | 0.0 otherwise                                      |                |

+-------+----------------------------------------------------+----------------+

|     2 | Force :math:`f_x` exerted on the wall              | force units    |

+-------+----------------------------------------------------+----------------+

|     3 | Force :math:`f_y` exerted on the wall              | force units    |

+-------+----------------------------------------------------+----------------+

|     4 | Force :math:`f_z` exerted on the wall              | force units    |

+-------+----------------------------------------------------+----------------+

|     5 | :math:`\Delta x` between wall surface and particle | distance units |

+-------+----------------------------------------------------+----------------+

|     6 | :math:`\Delta y` between wall surface and particle | distance units |

+-------+----------------------------------------------------+----------------+

|     7 | :math:`\Delta z` between wall surface and particle | distance units |

+-------+----------------------------------------------------+----------------+

|     8 | Radius :math:`r` of atom                           | distance units |

+-------+----------------------------------------------------+----------------+

None of the :doc:`fix_modify <fix_modify>` options are relevant to this fix.

No parameter of this fix can be used with the *start/stop* keywords of the

:doc:`run <run>` command. This fix is not invoked during :doc:`energy

minimization <minimize>`.

Restrictions

""""""""""""