Class Scine::Utils::Dimer

class Dimer : public Scine::Utils::Optimizer

An implementation of the Dimer optimization algorithm for saddlepoints.

transition state search without hessian by finding minimum curvature by gradient calculations of a dimer on PES dimer is constructed by estimated eigenvector or random vector, then dimer is rotated iteratively until it is aligned with lowest curvature mode, then translation is performed this is repeated until converged

Implemented, as described in: Kaestner J. and Sherwood P., Journal of Chemical Physics, 2008 Shang C. and Liu ZP., Journal of Chemical Theory and Computation, 2010

Public Functions

Dimer()

Default constructor.

template<class UpdateFunction>
int optimize(Eigen::VectorXd &parameters, UpdateFunction &&function, GradientBasedCheck &check)

The main routine of the optimizer that carries out the actual optimization.

Return

int Returns the number of optimization cycles carried out until the conclusion of the optimization function.

Template Parameters
  • UpdateFunction: A lambda function with a void return value, and the arguments:

    1. const Eigen::VectorXd& parameters

    2. double& value

    3. Eigen::VectorXd& gradients

Parameters
  • parameters: The parameters to be optimized.

  • function: The function to be evaluated in order to get values and gradients for a given set of parameters.

  • check: The ConvergenceCheck to be used in order to determine when the optimization is finished or should stop for other reasons.

virtual void addSettingsDescriptors(UniversalSettings::DescriptorCollection &collection) const

Adds all relevant options to the given UniversalSettings::DescriptorCollection thus expanding it to include the Dimers’s options.

Parameters
  • collection: The DescriptorCollection to which new fields shall be added.

virtual void applySettings(const Settings &settings)

Updates the Dimer’s options with those values given in the Settings.

Parameters
  • settings: The settings to update the option of the steepest descent with.

Public Members

double trustRadius = 0.5

The maximum RMS of a taken step.

double defaultTranslationStep = 1

The factor to multiple the stepsize vector in a steepest descent step.