qrunch.chemistry.ground_state_problem.builders.active_space_ground_state_problem_modifier

Complete active space ground state problem modifier.

Module Attributes

DEFAULT_ACTIVE_SPACE_OPTIONS

The default options for the active space modification.

Classes

`ActiveSpaceElectronConfiguration`	Active space electron configuration.
`ActiveSpaceGroundStateProblemModifier`	A Active space (AS) ground state problem modifier.
`ActiveSpaceOptions`	Options controlling the active-space reduction of two-body integrals.
`ActiveSpaceRestrictedGroundStateProblemModifier`	Modifier that can build a restricted active space ground state problem modifier.
`ActiveSpaceUnrestrictedGroundStateProblemModifier`	Modifier that can build a active space unrestricted ground state problem modifier.

class ActiveSpaceElectronConfiguration

Bases: object

Active space electron configuration.

All fields are immutable (frozen=True) so an instance can be safely reused.

Parameters:

number_of_active_spatial_orbitals – The number of spatial orbitals in the active space.
number_of_active_alpha_electrons – The number of alpha electrons in the active space.

__init__(number_of_active_spatial_orbitals: int, number_of_active_alpha_electrons: int) → None

Parameters:

number_of_active_spatial_orbitals (int)
number_of_active_alpha_electrons (int)

Return type:

None

number_of_active_alpha_electrons: int

number_of_active_spatial_orbitals: int

class ActiveSpaceGroundStateProblemModifier

Bases: GroundStateProblemModifier

A Active space (AS) ground state problem modifier.

__init__(active_space_electron_configuration: ActiveSpaceElectronConfiguration, options: ActiveSpaceOptions = ActiveSpaceOptions(reduction_tolerance=1e-10)) → None

Initialize a ActiveSpaceGroundStateProblemModifier.

The ActiveSpaceGroundStateProblemModifier modify an existing ground state problem to account for a active space (AS) calculation. It does so by creating a new ground state problem with a well-defined active space. This means that the integrals only include contributions from the active orbitals and the core hamiltonian is replaced by the inactive Fock matrix, which includes contributions from the inactive orbitals.

The new ground state problem include the inactive energy contribution, which is a constant energy arising from the inactive orbitals.

Parameters:

active_space_electron_configuration (ActiveSpaceElectronConfiguration) – The active space configuration to use in the builder.
options (ActiveSpaceOptions) – Options controlling the active-space integral reduction.

Return type:

None

modify(problem: RestrictedGroundStateProblem) → RestrictedGroundStateProblem

modify(problem: UnrestrictedGroundStateProblem) → UnrestrictedGroundStateProblem

Calculate the inactive Fock matrices and return the active space integrals.

The inactive Fock matrices include contributions from the inactive orbitals and are used in the Active Space (AS) calculation to account for interactions between active and inactive orbitals.

Parameters:: problem (RestrictedGroundStateProblem | UnrestrictedGroundStateProblem) – The ground state problem to modify.
Return type:: RestrictedGroundStateProblem | UnrestrictedGroundStateProblem

classmethod persistence_key() → str

Provide a unique persistence key for checkpointing after this modifier is applied.

Return type:: str

classmethod short_name() → str

Provide a short name for logging purposes.

Return type:: str

class ActiveSpaceOptions

Bases: DataclassPublicAPI

Options controlling the active-space reduction of two-body integrals.

All fields are immutable (frozen=True) so an instance can be safely reused.

Parameters:: reduction_tolerance – A reduction threshold. Currently, this is only used for RI-integrals, where the reduction tolerance is used as a reative threshold for pruning auxiliary basis functions. Thus, eigenvalues smaller than this relative threshold are discarded.

__init__(*, reduction_tolerance: float = 1e-10) → None

Parameters:: reduction_tolerance (float)
Return type:: None

reduction_tolerance: float = 1e-10

class ActiveSpaceRestrictedGroundStateProblemModifier

Bases: object

Modifier that can build a restricted active space ground state problem modifier.

__init__(active_space_electron_configuration: ActiveSpaceElectronConfiguration, options: ActiveSpaceOptions = ActiveSpaceOptions(reduction_tolerance=1e-10)) → None

Initialize a ActiveSpaceRestrictedGroundStateProblemModifier.

Parameters:

active_space_electron_configuration (ActiveSpaceElectronConfiguration) – The active space configuration to use in the builder.
options (ActiveSpaceOptions) – Options controlling the active-space integral reduction.

Return type:

None

modify(problem: RestrictedGroundStateProblem) → RestrictedGroundStateProblem

Calculate the inactive Fock matrices and return the active space integrals.

The inactive Fock matrices include contributions from the inactive orbitals and are used in the active space calculation to account for interactions between active and inactive orbitals.

Parameters:: problem (RestrictedGroundStateProblem) – The ground state problem to modify.
Return type:: RestrictedGroundStateProblem

classmethod short_name() → str

Provide a short name for logging purposes.

Return type:: str

class ActiveSpaceUnrestrictedGroundStateProblemModifier

Bases: object

Modifier that can build a active space unrestricted ground state problem modifier.

__init__(active_space_electron_configuration: ActiveSpaceElectronConfiguration, options: ActiveSpaceOptions = ActiveSpaceOptions(reduction_tolerance=1e-10)) → None

Initialize a ActiveSpaceRestrictedGroundStateProblemModifier.

Parameters:

active_space_electron_configuration (ActiveSpaceElectronConfiguration) – The active space configuration to use in the builder.
options (ActiveSpaceOptions) – Options controlling the active-space integral reduction.

Return type:

None

modify(problem: UnrestrictedGroundStateProblem) → UnrestrictedGroundStateProblem

Calculate the inactive Fock matrices and return the active space integrals.

The inactive Fock matrices include contributions from the inactive orbitals and are used in the Active Space calculation to account for interactions between active and inactive orbitals.

Parameters:: problem (UnrestrictedGroundStateProblem) – The ground state problem to modify.
Return type:: UnrestrictedGroundStateProblem

classmethod short_name() → str

Provide a short name for logging purposes.

Return type:: str

DEFAULT_ACTIVE_SPACE_OPTIONS = ActiveSpaceOptions(reduction_tolerance=1e-10): The default options for the active space modification.