relentless.simulate.DihedralPotentialTabulator

class relentless.simulate.DihedralPotentialTabulator(potentials, num)

Tabulate one or more dihedral potentials.

Enables evaluation of energy, force, and derivative at different dihedral values (i.e. \(\phi\)) on a range \(\left[ -\pi, \pi \right]\).

Parameters:

• potentials (DihedralPotential or array_like) – The dihedral potential(s) to be tabulated. If array_like, all elements must be DihedralPotentials.

• num (int) – The number of points (value of \(\phi\)) at which to tabulate and evaluate the potential.

Methods

derivative(key, var[, x])	Evaluates and accumulates derivative for all potentials.
energy(key[, x])	Evaluates and accumulates energy for all potentials.
force(key[, x])	Evaluates and accumulates force for all potentials.

Attributes

linear_space	x values spaced linearly from start to stop.
num	The number of points at which to tabulate/evaluate the potential, must be at least 2.
potentials	The individual potentials that are tabulated.
squared_space	x values spaced linearly from start**2` to ``stop**2.
start	The x value at which to start tabulation.
stop	The x value at which to stop tabulation.
types	The types of the potentials.

derivative(key, var, x=None)

Evaluates and accumulates derivative for all potentials.

Parameters:

• key (str) – The key for which to evaluate the derivative for each potential.

• var (Variable) – Variable to differentiate with respect to.

• x (float or list) – The pair distance(s) at which to evaluate the derivative. Default of None will use a linear space from start to stop.

Returns:

Accumulated force at each x value.

Return type:

array_like

energy(key, x=None)

Evaluates and accumulates energy for all potentials.

Parameters:

• key (str) – The key for which to evaluate the energy for each potential.

• x (float or list) – The pair distance(s) at which to evaluate the derivative. Default of None will use a linear space from start to stop.

Returns:

Accumulated energy at each x value.

Return type:

array_like

force(key, x=None)

Evaluates and accumulates force for all potentials.

Parameters:

• key (str) – The key for which to evaluate the force for each potential.

• x (float or list) – The pair distance(s) at which to evaluate the derivative. Default of None will use a linear space from start to stop.

Returns:

Accumulated force at each x value.

Return type:

array_like

property linear_space

x values spaced linearly from start to stop.

Type:

array_like

property num

The number of points at which to tabulate/evaluate the potential, must be at least 2.

Type:

int

property potentials

The individual potentials that are tabulated.

Type:

array_like

property squared_space

x values spaced linearly from start**2` to ``stop**2.

Type:

array_like

property start

The x value at which to start tabulation.

Type:

float

property stop

The x value at which to stop tabulation.

Type:

float

property types

The types of the potentials.

Type:

tuple