hpmc.integrate

Overview

hpmc.integrate.convex_polygon

HPMC integration for convex polygons (2D).

hpmc.integrate.convex_polyhedron

HPMC integration for convex polyhedra (3D).

hpmc.integrate.convex_spheropolygon

HPMC integration for convex spheropolygons (2D).

hpmc.integrate.convex_spheropolyhedron

HPMC integration for spheropolyhedra (3D).

hpmc.integrate.convex_spheropolyhedron_union

HPMC integration for unions of convex polyhedra (3D).

hpmc.integrate.ellipsoid

HPMC integration for ellipsoids (2D/3D).

hpmc.integrate.faceted_sphere

HPMC integration for faceted spheres (3D).

hpmc.integrate.interaction_matrix

Define pairwise interaction matrix

hpmc.integrate.mode_hpmc

Base class HPMC integrator.

hpmc.integrate.polyhedron

HPMC integration for general polyhedra (3D).

hpmc.integrate.simple_polygon

HPMC integration for simple polygons (2D).

hpmc.integrate.sphere

HPMC integration for spheres (2D/3D).

hpmc.integrate.sphere_union

HPMC integration for unions of spheres (3D).

hpmc.integrate.sphinx

HPMC integration for sphinx particles (3D).

Details

class hoomd.hpmc.integrate.convex_polygon(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for convex polygons (2D).

Parameters

  • seed (int) – Random number seed

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Note

For concave polygons, use simple_polygon.

Convex polygon parameters:

  • vertices (required) - vertices of the polygon as is a list of (x,y) tuples of numbers (distance units)

    • Vertices MUST be specified in a counter-clockwise order.

    • The origin MUST be contained within the vertices.

    • Points inside the polygon MUST NOT be included.

    • The origin centered circle that encloses all vertices should be of minimal size for optimal performance (e.g. don’t put the origin right next to an edge).

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Warning

HPMC does not check that all requirements are met. Undefined behavior will result if they are violated.

Examples:

mc = hpmc.integrate.convex_polygon(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', vertices=[(-0.5, -0.5), (0.5, -0.5), (0.5, 0.5), (-0.5, 0.5)]);
print('vertices = ', mc.shape_param['A'].vertices)
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'Polygon', 'rounding_radius': 0,
  'vertices': [[-0.5, -0.5], [0.5, -0.5], [0.5, 0.5], [-0.5, 0.5]]}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.convex_polyhedron(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for convex polyhedra (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – (Override the automatic choice for the number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Convex polyhedron parameters:

  • vertices (required) - vertices of the polyhedron as is a list of (x,y,z) tuples of numbers (distance units)

    • The origin MUST be contained within the vertices.

    • The origin centered circle that encloses all vertices should be of minimal size for optimal performance (e.g. don’t put the origin right next to a face).

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Warning

HPMC does not check that all requirements are met. Undefined behavior will result if they are violated.

Example:

mc = hpmc.integrate.convex_polyhedron(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', vertices=[(0.5, 0.5, 0.5), (0.5, -0.5, -0.5), (-0.5, 0.5, -0.5), (-0.5, -0.5, 0.5)]);
print('vertices = ', mc.shape_param['A'].vertices)

Depletants Example:

mc = hpmc.integrate.convex_polyhedron(seed=415236, d=0.3, a=0.4)
mc.set_param(nselect=1)
mc.shape_param.set('A', vertices=[(0.5, 0.5, 0.5), (0.5, -0.5, -0.5), (-0.5, 0.5, -0.5), (-0.5, -0.5, 0.5)]);
mc.shape_param.set('B', vertices=[(0.05, 0.05, 0.05), (0.05, -0.05, -0.05), (-0.05, 0.05, -0.05), (-0.05, -0.05, 0.05)]);
mc.set_fugacity('B',fugacity=3.0)
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'ConvexPolyhedron', 'rounding_radius': 0,
  'vertices': [[0.5, 0.5, 0.5], [0.5, -0.5, -0.5],
               [-0.5, 0.5, -0.5], [-0.5, -0.5, 0.5]]}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.convex_spheropolygon(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for convex spheropolygons (2D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Spheropolygon parameters:

  • vertices (required) - vertices of the polygon as is a list of (x,y) tuples of numbers (distance units)

    • The origin MUST be contained within the shape.

    • The origin centered circle that encloses all vertices should be of minimal size for optimal performance (e.g. don’t put the origin right next to an edge).

  • sweep_radius (default: 0.0) - the radius of the sphere swept around the edges of the polygon (distance units) - optional

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Useful cases:

  • A 1-vertex spheropolygon is a disk.

  • A 2-vertex spheropolygon is a spherocylinder.

Warning

HPMC does not check that all requirements are met. Undefined behavior will result if they are violated.

Examples:

mc = hpmc.integrate.convex_spheropolygon(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', vertices=[(-0.5, -0.5), (0.5, -0.5), (0.5, 0.5), (-0.5, 0.5)], sweep_radius=0.1, ignore_statistics=False);
mc.shape_param.set('A', vertices=[(0,0)], sweep_radius=0.5, ignore_statistics=True);
print('vertices = ', mc.shape_param['A'].vertices)
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'Polygon', 'rounding_radius': 0.1,
  'vertices': [[-0.5, -0.5], [0.5, -0.5], [0.5, 0.5], [-0.5, 0.5]]}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.convex_spheropolyhedron(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for spheropolyhedra (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

A spheropolyhedron can also represent spheres (0 or 1 vertices), and spherocylinders (2 vertices).

Spheropolyhedron parameters:

  • vertices (required) - vertices of the polyhedron as is a list of (x,y,z) tuples of numbers (distance units)

    • The origin MUST be contained within the vertices.

    • The origin centered sphere that encloses all vertices should be of minimal size for optimal performance (e.g. don’t put the origin right next to a face).

    • A sphere can be represented by specifying zero vertices (i.e. vertices=[]) and a non-zero radius R

    • Two vertices and a non-zero radius R define a prolate spherocylinder.

  • sweep_radius (default: 0.0) - the radius of the sphere swept around the edges of the polygon (distance units) - optional

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Warning

HPMC does not check that all requirements are met. Undefined behavior will result if they are violated.

Example:

mc = hpmc.integrate.convex_spheropolyhedron(seed=415236, d=0.3, a=0.4)
mc.shape_param['tetrahedron'].set(vertices=[(0.5, 0.5, 0.5), (0.5, -0.5, -0.5), (-0.5, 0.5, -0.5), (-0.5, -0.5, 0.5)]);
print('vertices = ', mc.shape_param['A'].vertices)
mc.shape_param['SphericalDepletant'].set(vertices=[], sweep_radius=0.1, ignore_statistics=True);

Depletants example:

mc = hpmc.integrate.convex_spheropolyhedron(seed=415236, d=0.3, a=0.4)
mc.shape_param['tetrahedron'].set(vertices=[(0.5, 0.5, 0.5), (0.5, -0.5, -0.5), (-0.5, 0.5, -0.5), (-0.5, -0.5, 0.5)]);
mc.shape_param['SphericalDepletant'].set(vertices=[], sweep_radius=0.1);
mc.set_fugacity('B',fugacity=3.0)
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'ConvexPolyhedron', 'rounding_radius': 0.1,
  'vertices': [[0.5, 0.5, 0.5], [0.5, -0.5, -0.5],
               [-0.5, 0.5, -0.5], [-0.5, -0.5, 0.5]]}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.convex_spheropolyhedron_union(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4)

HPMC integration for unions of convex polyhedra (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • capacity (int) – Set to the number of constituent convex polyhedra per leaf node

New in version 2.2.

Convex polyhedron union parameters:

  • vertices (required) - list of vertex lists of the polyhedra in particle coordinates.

  • centers (required) - list of centers of constituent polyhedra in particle coordinates.

  • orientations (required) - list of orientations of constituent polyhedra.

  • overlap (default: 1 for all particles) - only check overlap between constituent particles for which overlap [i] & overlap[j] is !=0, where ‘&’ is the bitwise AND operator.

  • sweep_radii (default: 0 for all particle) - radii of spheres sweeping out each constituent polyhedron

    • New in version 2.4.

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking.

Example:

mc = hpmc.integrate.convex_spheropolyhedron_union(seed=27, d=0.3, a=0.4)
cube_verts = [[-1,-1,-1],[-1,-1,1],[-1,1,1],[-1,1,-1],
             [1,-1,-1],[1,-1,1],[1,1,1],[1,1,-1]]
mc.shape_param.set('A', vertices=[cube_verts, cube_verts],
                        centers=[[-1,0,0],[1,0,0]],orientations=[[1,0,0,0],[1,0,0,0]]);
print('vertices of the first cube = ', mc.shape_param['A'].members[0].vertices)
print('center of the first cube = ', mc.shape_param['A'].centers[0])
print('orientation of the first cube = ', mc.shape_param['A'].orientations[0])
class hoomd.hpmc.integrate.ellipsoid(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for ellipsoids (2D/3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Ellipsoid parameters:

  • a (required) - principle axis a of the ellipsoid (radius in the x direction) (distance units)

  • b (required) - principle axis b of the ellipsoid (radius in the y direction) (distance units)

  • c (required) - principle axis c of the ellipsoid (radius in the z direction) (distance units)

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Example:

mc = hpmc.integrate.ellipsoid(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', a=0.5, b=0.25, c=0.125);
print('ellipsoids parameters (a,b,c) = ', mc.shape_param['A'].a, mc.shape_param['A'].b, mc.shape_param['A'].c)

Depletants Example:

mc = hpmc.integrate.ellipsoid(seed=415236, d=0.3, a=0.4)
mc.set_param(nselect=1)
mc.shape_param.set('A', a=0.5, b=0.25, c=0.125);
mc.shape_param.set('B', a=0.05, b=0.05, c=0.05);
mc.set_fugacity('B',fugacity=3.0)
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'Ellipsoid', 'a': 1.0, 'b': 1.5, 'c': 1}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.faceted_ellipsoid(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for faceted ellipsoids (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

A faceted ellipsoid is an ellipsoid intersected with a convex polyhedron defined through halfspaces. The equation defining each halfspace is given by:

\[n_i\cdot r + b_i \le 0\]

where \(n_i\) is the face normal, and \(b_i\) is the offset.

Warning

The origin must be chosen so as to lie inside the shape, or the overlap check will not work. This condition is not checked.

Faceted ellipsoid parameters:

  • normals (required) - list of (x,y,z) tuples defining the facet normals (distance units)

  • offsets (required) - list of offsets (distance unit^2)

  • a (required) - first half axis of ellipsoid

  • b (required) - second half axis of ellipsoid

  • c (required) - third half axis of ellipsoid

  • vertices (required) - list of vertices for intersection polyhedron

  • origin (required) - origin vector

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Warning

Planes must not be coplanar.

Note

The half-space intersection of the normals has to match the convex polyhedron defined by the vertices (if non-empty), currently the half-space intersection is not calculated automatically. For simple intersections with planes that do not intersect within the sphere, the vertices list can be left empty.

Example:

mc = hpmc.integrate.faceted_ellipsoid(seed=415236, d=0.3, a=0.4)

# half-space intersection
slab_normals = [(-1,0,0),(1,0,0),(0,-1,0),(0,1,0),(0,0,-1),(0,0,1)]
slab_offsets = [-0.1,-1,-.5,-.5,-.5,-.5)

# polyedron vertices
slab_verts = [[-.1,-.5,-.5],[-.1,-.5,.5],[-.1,.5,.5],[-.1,.5,-.5], [1,-.5,-.5],[1,-.5,.5],[1,.5,.5],[1,.5,-.5]]

mc.shape_param.set('A', normals=slab_normals, offsets=slab_offsets, vertices=slab_verts,a=1.0, b=0.5, c=0.5);
print('a = {}, b = {}, c = {}', mc.shape_param['A'].a,mc.shape_param['A'].b,mc.shape_param['A'].c)

Depletants Example:

mc = hpmc.integrate.faceted_ellipsoid(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', normals=[(-1,0,0),(1,0,0),(0,-1,0),(0,1,0),(0,0,-1),(0,0,1)],a=1.0, b=0.5, c=0.25);
# depletant sphere
mc.shape_param.set('B', normals=[],a=0.1,b=0.1,c=0.1);
mc.set_fugacity('B',fugacity=3.0)
class hoomd.hpmc.integrate.faceted_ellipsoid_union(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4)

HPMC integration for unions of faceted ellipsoids (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • capacity (int) – Set to the number of constituent convex polyhedra per leaf node

New in version 2.5.

See faceted_ellipsoid for a detailed explanation of the constituent particle parameters.

Faceted ellipsiod union parameters:

  • normals (required) - list of list of (x,y,z) tuples defining the facet normals (distance units)

  • offsets (required) - list of list of offsets (distance unit^2)

  • axes (required) - list of half axes, tuple of three per constituent ellipsoid

  • vertices (required) - list of list list of vertices for intersection polyhedron

  • origin (required) - list of origin vectors

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking.

Example:

mc = hpmc.integrate.faceted_ellipsoid_union(seed=27, d=0.3, a=0.4)

# make a prolate Janus ellipsoid
# cut away -x halfspace
normals = [(-1,0,0)]
offsets = [0]

mc.shape_param.set('A', normals=[normals, normals],
                        offsets=[offsets, offsets],
                        vertices=[[], []],
                        axes=[(.5,.5,2),(.5,.5,2)],
                        centers=[[0,0,0],[0,0,0]],
                        orientations=[[1,0,0,0],[0,0,0,-1]]);

print('offsets of the first faceted ellipsoid = ', mc.shape_param['A'].members[0].normals)
print('normals of the first faceted ellispoid = ', mc.shape_param['A'].members[0].offsets)
print('vertices of the first faceted ellipsoid = ', mc.shape_param['A'].members[0].vertices)
class hoomd.hpmc.integrate.faceted_sphere(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for faceted spheres (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

A faceted sphere is a sphere intersected with halfspaces. The equation defining each halfspace is given by:

\[n_i\cdot r + b_i \le 0\]

where \(n_i\) is the face normal, and \(b_i\) is the offset.

Warning

The origin must be chosen so as to lie inside the shape, or the overlap check will not work. This condition is not checked.

Faceted sphere parameters:

  • normals (required) - list of (x,y,z) tuples defining the facet normals (distance units)

  • offsets (required) - list of offsets (distance unit^2)

  • diameter (required) - diameter of sphere

  • vertices (required) - list of vertices for intersection polyhedron

  • origin (required) - origin vector

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Warning

Planes must not be coplanar.

Note

The half-space intersection of the normals has to match the convex polyhedron defined by the vertices (if non-empty), currently the half-space intersection is not calculated automatically. For simple intersections with planes that do not intersect within the sphere, the vertices list can be left empty.

Example::

# half-space intersection slab_normals = [(-1,0,0),(1,0,0),(0,-1,0),(0,1,0),(0,0,-1),(0,0,1)] slab_offsets = [-0.1,-1,-.5,-.5,-.5,-.5)

# polyedron vertices slab_verts = [[-.1,-.5,-.5],[-.1,-.5,.5],[-.1,.5,.5],[-.1,.5,-.5], [.5,-.5,-.5],[.5,-.5,.5],[.5,.5,.5],[.5,.5,-.5]]

mc = hpmc.integrate.faceted_sphere(seed=415236, d=0.3, a=0.4) mc.shape_param.set(‘A’, normals=slab_normals,offsets=slab_offsets, vertices=slab_verts,diameter=1.0); print(‘diameter = ‘, mc.shape_param[‘A’].diameter)

Depletants Example:

mc = hpmc.integrate.faceted_sphere(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', normals=[(-1,0,0),(1,0,0),(0,-1,0),(0,1,0),(0,0,-1),(0,0,1)],diameter=1.0);
mc.shape_param.set('B', normals=[],diameter=0.1);
mc.set_fugacity('B',fugacity=3.0)
class hoomd.hpmc.integrate.interaction_matrix

Define pairwise interaction matrix

All shapes use interaction_matrix to define the interaction matrix between different pairs of particles indexed by type. The set of pair coefficients is a symmetric matrix defined over all possible pairs of particle types.

By default, all elements of the interaction matrix are 1, that means that overlaps are checked between all pairs of types. To disable overlap checking for a specific type pair, set the coefficient for that pair to 0.

Access the interaction matrix with a saved integrator object like so:

from hoomd import hpmc

mc = hpmc.integrate.some_shape(arguments...)
mv.overlap_checks.set('A', 'A', enable=False)
mc.overlap_checks.set('A', 'B', enable=True)
mc.overlap_checks.set('B', 'B', enable=False)

New in version 2.1.

set(a, b, enable)

Sets parameters for one type pair.

Parameters

  • a (str) – First particle type in the pair (or a list of type names)

  • b (str) – Second particle type in the pair (or a list of type names)

  • enable – Set to True to enable overlap checks for this pair, False otherwise

By default, all interaction matrix elements are set to ‘True’.

It is not an error, to specify matrix elements for particle types that do not exist in the simulation.

There is no need to specify matrix elements for both pairs ‘A’, ‘B’ and ‘B’, ‘A’. Specifying only one is sufficient.

To set the same elements between many particle types, provide a list of type names instead of a single one. All pairs between the two lists will be set to the same parameters.

Examples:

mc.overlap_checks.set('A', 'A', False);
mc.overlap_checks.set('B', 'B', False);
mc.overlap_checks.set('A', 'B', True);
mc.overlap_checks.set(['A', 'B', 'C', 'D'], 'F', True);
mc.overlap_checks.set(['A', 'B', 'C', 'D'], ['A', 'B', 'C', 'D'], False);
class hoomd.hpmc.integrate.mode_hpmc

Base class HPMC integrator.

mode_hpmc is the base class for all HPMC integrators. It provides common interface elements. Users should not instantiate this class directly. Methods documented here are available to all hpmc integrators.

State data

HPMC integrators can save and restore the following state information to gsd files:

  • Maximum trial move displacement d

  • Maximum trial rotation move a

  • Shape parameters for all types.

State data are not written by default. You must explicitly request that state data for an mc integrator is written to a gsd file (see hoomd.dump.gsd.dump_state()).

mc = hoomd.hpmc.shape(...)
gsd = hoomd.dump.gsd(...)
gsd.dump_state(mc)

State data are not restored by default. You must explicitly request that state data be restored when initializing the integrator.

init.read_gsd(...)
mc = hoomd.hpmc.shape(..., restore_state=True)

See the State data section of the HOOMD GSD schema for details on GSD data chunk names and how the data are stored.

count_overlaps()

Count the number of overlaps.

Returns

The number of overlaps in the current system configuration

Example:

mc = hpmc.integrate.shape(..);
mc.shape_param.set(....);
run(100)
num_overlaps = mc.count_overlaps();
get_a(type=None)

Get the maximum trial rotation.

Parameters

type (str) – Type name to query.

Returns

The current value of the ‘a’ parameter of the integrator.

get_counters()

Get all trial move counters.

Returns

A dictionary containing all trial moves counted during the last hoomd.run().

The dictionary contains the entries:

  • translate_accept_count - count of the number of accepted translate moves

  • translate_reject_count - count of the number of rejected translate moves

  • rotate_accept_count - count of the number of accepted rotate moves

  • rotate_reject_count - count of the number of rejected rotate moves

  • overlap_checks - estimate of the number of overlap checks performed

  • translate_acceptance - Average translate acceptance ratio over the run

  • rotate_acceptance - Average rotate acceptance ratio over the run

  • move_count - Count of the number of trial moves during the run

get_d(type=None)

Get the maximum trial displacement.

Parameters

type (str) – Type name to query.

Returns

The current value of the ‘d’ parameter of the integrator.

get_fugacity(type)
Get depletant fugacity of a given type

  • New in version 3.0.

Parameters

type (str) – Type for which fugacity is returned

get_move_ratio()

Get the current probability of attempting translation moves.

Returns: The current value of the ‘move_ratio’ parameter of the integrator.

get_mps()

Get the number of trial moves per second.

Returns

The number of trial moves per second performed during the last hoomd.run().

get_nselect()

Get nselect parameter.

Returns

The current value of the ‘nselect’ parameter of the integrator.

get_quermass_mode()

Get the value of the quermass integration setting

Returns

The current value of the ‘quermass’ parameter of the integrator

get_rotate_acceptance()

Get the average acceptance ratio for rotate moves.

Returns

The average rotate accept ratio during the last hoomd.run().

Example:

mc = hpmc.integrate.shape(..);
mc.shape_param.set(....);
run(100)
t_accept = mc.get_rotate_acceptance();
get_sweep_radius()

Get the value of the additional sweep radius for depletant simulations

Returns

The current value of the ‘sweep_radius’ parameter of the integrator

get_translate_acceptance()

Get the average acceptance ratio for translate moves.

Returns

The average translate accept ratio during the last hoomd.run().

Example:

mc = hpmc.integrate.shape(..);
mc.shape_param.set(....);
run(100)
t_accept = mc.get_translate_acceptance();
get_type_shapes()

Get all the types of shapes in the current simulation.

Since this behaves differently for different types of shapes, the default behavior just raises an exception. Subclasses can override this to properly return.

map_energies()

Build an energy map of the system

Returns

List of tuples. The i,j entry contains the pairwise interaction energy of the ith and jth particles (by tag)

Note

map_energies() does not support MPI parallel simulations.

Example

mc = hpmc.integrate.shape(…) mc.shape_param.set(…) energy_map = np.asarray(mc.map_energies())

map_overlaps()

Build an overlap map of the system

Returns

List of tuples. True/false value of the i,j entry indicates overlap/non-overlap of the ith and jth particles (by tag)

Note

map_overlaps() does not support MPI parallel simulations.

Example

mc = hpmc.integrate.shape(…) mc.shape_param.set(…) overlap_map = np.asarray(mc.map_overlaps())

restore_state()

Restore the state information from the file used to initialize the simulations

set_fugacity(type, fugacity)
Set depletant fugacity of a given type

  • New in version 3.0.

Parameters

  • type (str) – Type for which fugacity is returned

  • fugacity (float) – Ideal gas density of the depletant, can take any scalar value

set_params(d=None, a=None, move_ratio=None, nselect=None, quermass=None, sweep_radius=None, deterministic=None)

Changes parameters of an existing integration mode.

Parameters

  • d (float) – (if set) Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – (if set) Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – (if set) New value for the move ratio.

  • nselect (int) – (if set) New value for the number of particles to select for trial moves in one cell.

  • quermass (bool) – (if set) Implicit depletants only: Enable/disable quermass integration mode

  • sweep_radius (float) – (if set): Implicit depletants only: Additional radius of a sphere to sweep the shapes by in quermass mode

  • deterministic (bool) – (if set) Make HPMC integration deterministic on the GPU by sorting the cell list.

Note

Simulations are only deterministic with respect to the same execution configuration (CPU or GPU) and number of MPI ranks. Simulation output will not be identical if either of these is changed.

test_overlap(type_i, type_j, rij, qi, qj, use_images=True, exclude_self=False)

Test overlap between two particles.

Parameters

  • type_i (str) – Type of first particle

  • type_j (str) – Type of second particle

  • rij (tuple) – Separation vector rj-ri between the particle centers

  • qi (tuple) – Orientation quaternion of first particle

  • qj (tuple) – Orientation quaternion of second particle

  • use_images (bool) – If True, check for overlap between the periodic images of the particles by adding the image vector to the separation vector

  • exclude_self (bool) – If both use_images and exclude_self are true, exclude the primary image

For two-dimensional shapes, pass the third dimension of rij as zero.

Returns

True if the particles overlap.

class hoomd.hpmc.integrate.polyhedron(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for general polyhedra (3D).

This shape uses an internal OBB tree for fast collision queries. Depending on the number of constituent spheres in the tree, different values of the number of spheres per leaf node may yield different optimal performance. The capacity of leaf nodes is configurable.

Only triangle meshes and spheres are supported. The mesh must be free of self-intersections.

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Polyhedron parameters:

  • vertices (required) - vertices of the polyhedron as is a list of (x,y,z) tuples of numbers (distance units)

    • The origin MUST strictly be contained in the generally nonconvex volume defined by the vertices and faces

    • The (0,0,0) centered sphere that encloses all vertices should be of minimal size for optimal performance (e.g. don’t translate the shape such that (0,0,0) right next to a face).

  • faces (required) - a list of vertex indices for every face

    • For visualization purposes, the faces MUST be defined with a counterclockwise winding order to produce an outward normal.

  • sweep_radius (default: 0.0) - rounding radius applied to polyhedron

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

  • capacity (default: 4) - set to the maximum number of particles per leaf node for better performance

    • New in version 2.2.

  • origin (default: (0,0,0)) - a point strictly inside the shape, needed for correctness of overlap checks

    • New in version 2.2.

  • hull_only (default: True) - if True, only consider intersections between hull polygons

    • New in version 2.2.

Warning

HPMC does not check that all requirements are met. Undefined behavior will result if they are violated.

Example:

mc = hpmc.integrate.polyhedron(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', vertices=[(-0.5, -0.5, -0.5), (-0.5, -0.5, 0.5), (-0.5, 0.5, -0.5), (-0.5, 0.5, 0.5), \
         (0.5, -0.5, -0.5), (0.5, -0.5, 0.5), (0.5, 0.5, -0.5), (0.5, 0.5, 0.5)],\
faces = [[0, 2, 6], [6, 4, 0], [5, 0, 4], [5,1,0], [5,4,6], [5,6,7], [3,2,0], [3,0,1], [3,6,2], \
         [3,7,6], [3,1,5], [3,5,7]]
print('vertices = ', mc.shape_param['A'].vertices)
print('faces = ', mc.shape_param['A'].faces)

Depletants Example:

mc = hpmc.integrate.polyhedron(seed=415236, d=0.3, a=0.4)
mc.set_param(nselect=1)
cube_verts = [(-0.5, -0.5, -0.5), (-0.5, -0.5, 0.5), (-0.5, 0.5, -0.5), (-0.5, 0.5, 0.5), \
             (0.5, -0.5, -0.5), (0.5, -0.5, 0.5), (0.5, 0.5, -0.5), (0.5, 0.5, 0.5)];
cube_faces = [[0, 2, 6], [6, 4, 0], [5, 0, 4], [5,1,0], [5,4,6], [5,6,7], [3,2,0], [3,0,1], [3,6,2], \
             [3,7,6], [3,1,5], [3,5,7]]
tetra_verts = [(0.5, 0.5, 0.5), (0.5, -0.5, -0.5), (-0.5, 0.5, -0.5), (-0.5, -0.5, 0.5)];
tetra_faces = [[0, 1, 2], [3, 0, 2], [3, 2, 1], [3,1,0]];
mc.shape_param.set('A', vertices = cube_verts, faces = cube_faces);
mc.shape_param.set('B', vertices = tetra_verts, faces = tetra_faces, origin = (0,0,0));
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'Mesh', 'vertices': [[0.5, 0.5, 0.5], [0.5, -0.5, -0.5], [-0.5, 0.5, -0.5], [-0.5, -0.5, 0.5]],
  'indices': [[0, 1, 2], [0, 3, 1], [0, 2, 3], [1, 3, 2]]}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.simple_polygon(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for simple polygons (2D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Note

For simple polygons that are not concave, use convex_polygon, it will execute much faster than simple_polygon.

Simple polygon parameters:

  • vertices (required) - vertices of the polygon as is a list of (x,y) tuples of numbers (distance units)

    • Vertices MUST be specified in a counter-clockwise order.

    • The polygon may be concave, but edges must not cross.

    • The origin doesn’t necessarily need to be inside the shape.

    • The origin centered circle that encloses all vertices should be of minimal size for optimal performance.

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Warning

HPMC does not check that all requirements are met. Undefined behavior will result if they are violated.

Examples:

mc = hpmc.integrate.simple_polygon(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', vertices=[(0, 0.5), (-0.5, -0.5), (0, 0), (0.5, -0.5)]);
print('vertices = ', mc.shape_param['A'].vertices)
get_type_shapes()

Get all the types of shapes in the current simulation.

Example

>>> mc.get_type_shapes()
[{'type': 'Polygon', 'rounding_radius': 0,
  'vertices': [[-0.5, -0.5], [0.5, -0.5], [0.5, 0.5], [-0.5, 0.5]]}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.sphere(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for spheres (2D/3D).

Parameters

  • seed (int) – Random number seed

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float, only with orientable=True) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type. (added in version 2.3)

  • move_ratio (float, only used with orientable=True) – Ratio of translation moves to rotation moves. (added in version 2.3)

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Hard particle Monte Carlo integration method for spheres.

Sphere parameters:

  • diameter (required) - diameter of the sphere (distance units)

  • orientable (default: False) - set to True for spheres with orientation (added in version 2.3)

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Examples:

mc = hpmc.integrate.sphere(seed=415236, d=0.3)
mc.shape_param.set('A', diameter=1.0)
mc.shape_param.set('B', diameter=2.0)
mc.shape_param.set('C', diameter=1.0, orientable=True)
print('diameter = ', mc.shape_param['A'].diameter)

Depletants Example:

mc = hpmc.integrate.sphere(seed=415236, d=0.3, a=0.4)
mc.set_param(nselect=8)
mc.shape_param.set('A', diameter=1.0)
mc.shape_param.set('B', diameter=.1)
mc.set_fugacity('B',fugacity=3.0)
get_type_shapes()

Get all the types of shapes in the current simulation.

Examples

The types will be ‘Sphere’ regardless of dimensionality.

>>> mc.get_type_shapes()
[{'type': 'Sphere', 'diameter': 1}, {'type': 'Sphere', 'diameter': 2}]
Returns

A list of dictionaries, one for each particle type in the system.

class hoomd.hpmc.integrate.sphere_union(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for unions of spheres (3D).

This shape uses an internal OBB tree for fast collision queries. Depending on the number of constituent spheres in the tree, different values of the number of spheres per leaf node may yield different optimal performance. The capacity of leaf nodes is configurable.

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • capacity (int) – Set to the number of constituent spheres per leaf node. (added in version 2.2)

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Sphere union parameters:

  • diameters (required) - list of diameters of the spheres (distance units).

  • centers (required) - list of centers of constituent spheres in particle coordinates.

  • overlap (default: 1 for all spheres) - only check overlap between constituent particles for which overlap [i] & overlap[j] is !=0, where ‘&’ is the bitwise AND operator.

    • New in version 2.1.

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking.

  • capacity (default: 4) - set to the maximum number of particles per leaf node for better performance

    • New in version 2.2.

Example:

mc = hpmc.integrate.sphere_union(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', diameters=[1.0, 1.0], centers=[(-0.25, 0.0, 0.0), (0.25, 0.0, 0.0)]);
print('diameter of the first sphere = ', mc.shape_param['A'].members[0].diameter)
print('center of the first sphere = ', mc.shape_param['A'].centers[0])

Depletants Example:

mc = hpmc.integrate.sphere_union(seed=415236, d=0.3, a=0.4)
mc.set_param(nselect=1)
mc.shape_param.set('A', diameters=[1.0, 1.0], centers=[(-0.25, 0.0, 0.0), (0.25, 0.0, 0.0)]);
mc.shape_param.set('B', diameters=[0.05], centers=[(0.0, 0.0, 0.0)]);
mc.set_fugacity('B',fugacity=3.0)
class hoomd.hpmc.integrate.sphinx(seed, d=0.1, a=0.1, move_ratio=0.5, nselect=4, restore_state=False)

HPMC integration for sphinx particles (3D).

Parameters

  • seed (int) – Random number seed.

  • d (float) – Maximum move displacement, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • a (float) – Maximum rotation move, Scalar to set for all types, or a dict containing {type:size} to set by type.

  • move_ratio (float) – Ratio of translation moves to rotation moves.

  • nselect (int) – The number of trial moves to perform in each cell.

  • restore_state (bool) – Restore internal state from initialization file when True. See mode_hpmc for a description of what state data restored. (added in version 2.2)

Sphinx particles are dimpled spheres (spheres with ‘positive’ and ‘negative’ volumes).

Sphinx parameters:

  • diameters - diameters of spheres (positive OR negative real numbers)

  • centers - centers of spheres in local coordinate frame

  • ignore_statistics (default: False) - set to True to disable ignore for statistics tracking

Quick Example:

mc = hpmc.integrate.sphinx(seed=415236, d=0.3, a=0.4)
mc.shape_param.set('A', centers=[(0,0,0),(1,0,0)], diameters=[1,.25])
print('diameters = ', mc.shape_param['A'].diameters)

Depletants Example:

mc = hpmc.integrate.sphinx(seed=415236, d=0.3, a=0.4)
mc.set_param(nselect=1)
mc.shape_param.set('A', centers=[(0,0,0),(1,0,0)], diameters=[1,-.25])
mc.shape_param.set('B', centers=[(0,0,0)], diameters=[.15])
mc.set_fugacity('B',fugacity=3.0)