qrunch.chemistry.reaction_path_problem.calculators.trim_ci_reaction_path_problem_calculators

Reaction path energy calculator using Trimmed CI.

Classes

TrimCIReactionPathProblemCalculator

Class for performing trimmed configuration interaction calculations on reactions.
class TrimCIReactionPathProblemCalculator

Bases: object

Class for performing trimmed configuration interaction calculations on reactions.

__init__(options: TrimCIOptions | None = None, *, paired_electron_approximation: bool = False) → None

Initialize instance of the trimmed configuration interaction calculator for reaction path problems.

Parameters:

  • options (TrimCIOptions | None) – Options to use for the calculation. None results in default options.

  • paired_electron_approximation (bool) – If True, only paired alpha/beta excitations are used during expansion. This restricts the CI space to determinants reachable via simultaneous identical excitations in both spin channels.

Return type:

None

calculate(reaction_path_problem: RestrictedReactionPathProblem | UnrestrictedReactionPathProblem) → ReactionPathProblemCalculatorResult

Solve the trimmed configuration interaction calculation.

The Trimmed CI energy is calculated for every geometry along the reaction path using the Trimmed CI ground state problem calculator.

The Hamiltonian for all geometries are assumed to be real.

Lazy on-disk ground state problems (see LazyRestrictedGroundStateProblem and LazyUnrestrictedGroundStateProblem) are materialised one at a time via manifest() and released as soon as their result has been computed, keeping peak memory usage bounded by a single ground state problem.

Parameters:

reaction_path_problem (RestrictedReactionPathProblem | UnrestrictedReactionPathProblem) – The reaction path problem to solve.

Return type:

ReactionPathProblemCalculatorResult