pymatgen.analysis.energy_models module

This module implements a EnergyModel abstract class and some basic implementations. Basically, an EnergyModel is any model that returns an “energy” for any given structure.

class EnergyModel[source]

Bases: MSONable

Abstract structure filter class.

classmethod from_dict(d)[source]
Parameters:

d – Dict representation

Returns:

EnergyModel

abstract get_energy(structure) → float[source]
Parameters:

structure – Structure

Returns:

Energy value

class EwaldElectrostaticModel(real_space_cut=None, recip_space_cut=None, eta=None, acc_factor=8.0)[source]

Bases: EnergyModel

Wrapper around EwaldSum to calculate the electrostatic energy.

Initializes the model. Args have the same definitions as in pymatgen.analysis.ewald.EwaldSummation.

Parameters:

  • real_space_cut (float) – Real space cutoff radius dictating how many terms are used in the real space sum. Defaults to None, which means determine automagically using the formula given in gulp 3.1 documentation.

  • recip_space_cut (float) – Reciprocal space cutoff radius. Defaults to None, which means determine automagically using the formula given in gulp 3.1 documentation.

  • eta (float) – Screening parameter. Defaults to None, which means determine automatically.

  • acc_factor (float) – No. of significant figures each sum is converged to.

as_dict()[source]
Returns:

MSONable dict

get_energy(structure)[source]
Parameters:

structure – Structure

Returns:

Energy value

class IsingModel(j, max_radius)[source]

Bases: EnergyModel

A very simple Ising model, with r^2 decay.

Parameters:

  • j (float) – The interaction parameter. E = J * spin1 * spin2.

  • radius (float) – max_radius for the interaction.

as_dict()[source]
Returns:

MSONable dict

get_energy(structure)[source]
Parameters:

structure – Structure

Returns:

Energy value

class NsitesModel[source]

Bases: EnergyModel

Sets the energy to the number of sites. More sites => higher “energy”. Used to rank structures from smallest number of sites to largest number of sites after enumeration.

as_dict()[source]
Returns:

MSONable dict

get_energy(structure)[source]
Parameters:

structure – Structure

Returns:

Energy value

class SymmetryModel(symprec: float = 0.1, angle_tolerance=5)[source]

Bases: EnergyModel

Sets the energy to the -ve of the spacegroup number. Higher symmetry => lower “energy”.

Args have same meaning as in pymatgen.symmetry.finder.SpacegroupAnalyzer.

Parameters:

  • symprec (float) – Symmetry tolerance. Defaults to 0.1.

  • angle_tolerance (float) – Tolerance for angles. Defaults to 5 degrees.

as_dict()[source]
Returns:

MSONable dict

get_energy(structure)[source]
Parameters:

structure – Structure

Returns:

Energy value