Periodic¶

class hoomd.md.dihedral.Periodic¶

Bases: Dihedral

Periodic dihedral force.

Periodic computes forces, virials, and energies on all dihedrals in the simulation state with:

\[U(\phi) = \frac{1}{2}k \left( 1 + d \cos\left(n \phi - \phi_0 \right) \right)\]

Examples:

harmonic = dihedral.Periodic()
harmonic.params["A-A-A-A"] = dict(k=3.0, d=-1, n=3, phi0=0)
harmonic.params["A-B-C-D"] = dict(k=100.0, d=1, n=4, phi0=math.pi / 2)

Members inherited from AutotunedObject:

property kernel_parameters¶: Kernel parameters. Read more...

property is_tuning_complete¶: Check if kernel parameter tuning is complete. Read more...

tune_kernel_parameters()¶: Start tuning kernel parameters. Read more...

Members inherited from Force:

additional_energy¶: Additional energy term. Read more...

additional_virial¶: Additional virial tensor term \(W_\mathrm{additional}\). Read more...

cpu_local_force_arrays¶: Local force arrays on the CPU. Read more...

energies¶: Energy contribution \(U_i\) from each particle. Read more...

energy¶: The potential energy \(U\) of the system from this force. Read more...

forces¶: The force \(\vec{F}_i\) applied to each particle. Read more...

gpu_local_force_arrays¶: Local force arrays on the GPU. Read more...

torques¶: The torque \(\vec{\tau}_i\) applied to each particle. Read more...

virials¶: Virial tensor contribution \(W_i\) from each particle. Read more...

Members defined in Periodic:

params¶

The parameter of the harmonic bonds for each dihedral type. The dictionary has the following keys:

k (float, required) - potential constant \(k\) \([\mathrm{energy}]\)
d (float, required) - sign factor \(d\)
n (int, required) - angle multiplicity factor \(n\)
phi0 (float, required) - phase shift \(\phi_0\) \([\mathrm{radians}]\)

Type:: TypeParameter [dihedral type, dict]