Skip to content

Commit

Permalink
Merge remote-tracking branch 'github/develop' into collected-small-fixes
Browse files Browse the repository at this point in the history
  • Loading branch information
akohlmey committed Nov 17, 2023
2 parents a4da559 + 9a43234 commit ab183eb
Show file tree
Hide file tree
Showing 5 changed files with 277 additions and 93 deletions.
6 changes: 3 additions & 3 deletions doc/src/Howto_body.rst
Original file line number Diff line number Diff line change
Expand Up @@ -170,9 +170,9 @@ with this body style to compute body/body and body/non-body interactions.
The *rounded/polygon* body style represents body particles as a 2d
polygon with a variable number of N vertices. This style can only be
used for 2d models; see the :doc:`boundary <boundary>` command. See the
"pair_style body/rounded/polygon" page for a diagram of two
squares with rounded circles at the vertices. Special cases for N = 1
(circle) and N = 2 (rod with rounded ends) can also be specified.
:doc:`pair_style body/rounded/polygon <pair_body_rounded_polygon>` page for
a diagram of two squares with rounded circles at the vertices. Special cases
for N = 1 (circle) and N = 2 (rod with rounded ends) can also be specified.

One use of this body style is for 2d discrete element models, as
described in :ref:`Fraige <body-Fraige>`.
Expand Down
16 changes: 13 additions & 3 deletions doc/src/fix_pimd.rst
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ Syntax

.. parsed-literal::
*keywords* = *method* or *integrator* or *ensemble* or *fmmode* or *fmass* or *scale* or *temp* or *thermostat* or *tau* or *iso* or *aniso* or *barostat* or *taup* or *fixcom* or *lj*
*method* value = *nmpimd*
*method* value = *nmpimd* (default) or *pimd*
*integrator* value = *obabo* or *baoab*
*fmmode* value = *physical* or *normal*
*fmass* value = scaling factor on mass
Expand Down Expand Up @@ -137,8 +137,6 @@ normal-mode PIMD. A value of *cmd* is for centroid molecular dynamics
the real particle.

.. note::
Fix pimd/langevin only supports *method* value *nmpimd*. This should be enough
for most PIMD applications for quantum thermodynamics purpose.

Motion of the centroid can be effectively uncoupled from the other
normal modes by scaling the fictitious masses to achieve a partial
Expand All @@ -151,6 +149,16 @@ normal-mode PIMD. A value of *cmd* is for centroid molecular dynamics
only the k > 0 modes are thermostatted, not the centroid degrees of
freedom.

.. versionadded:: TBD

Mode *pimd* added to fix pimd/langevin.

Fix pimd/langevin supports the *method* values *nmpimd* and *pimd*. The default value is *nmpimd*.
If *method* is *nmpimd*, the normal mode representation is used to integrate the equations of motion.
The exact solution of harmonic oscillator is used to propagate the free ring polymer part of the Hamiltonian.
If *method* is *pimd*, the Cartesian representation is used to integrate the equations of motion.
The harmonic force is added to the total force of the system, and the numerical integrator is used to propagate the Hamiltonian.

The keyword *integrator* specifies the Trotter splitting method used by *fix pimd/langevin*.
See :ref:`(Liu) <Liu>` for a discussion on the OBABO and BAOAB splitting schemes. Typically
either of the two should work fine.
Expand Down Expand Up @@ -207,6 +215,7 @@ The keyword *thermostat* reads *style* and *seed* of thermostat for fix style *p
be *PILE_L* (path integral Langevin equation local thermostat, as described in :ref:`Ceriotti <Ceriotti2>`), and *seed* should a positive integer number, which serves as the seed of the pseudo random number generator.

.. note::

The fix style *pimd/langevin* uses the stochastic PILE_L thermostat to control temperature. This thermostat works on the normal modes
of the ring polymer. The *tau* parameter controls the centroid mode, and the *scale* parameter controls the non-centroid modes.

Expand Down Expand Up @@ -269,6 +278,7 @@ related tasks for each of the partitions, e.g.
read_restart system_${ibead}.restart2
.. note::

Fix *pimd/langevin* dumps the Cartesian coordinates, but dumps the velocities and
forces in the normal mode representation. If the Cartesian velocities and forces are
needed, it is easy to perform the transformation when doing post-processing.
Expand Down
2 changes: 1 addition & 1 deletion doc/src/pair_body_rounded_polyhedron.rst
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ rounded/polyhedron particles.
This pairwise interaction between the rounded polyhedra is described
in :ref:`Wang <pair-Wang>`, where a polyhedron does not have sharp corners
and edges, but is rounded at its vertices and edges by spheres
centered on each vertex with a specified diameter. The edges if the
centered on each vertex with a specified diameter. The edges of the
polyhedron are defined between pairs of adjacent vertices. Its faces
are defined by a loop of edges. The sphere diameter for each polygon
is specified in the data file read by the :doc:`read data <read_data>`
Expand Down
Loading

0 comments on commit ab183eb

Please sign in to comment.