sc::FinDispMolecularHessian(3)

NAME

okay bestie, welcome to the MPQC manual page for sc::FinDispMolecularHessian(3) 💖 — the class that computes the molecular hessian by finite displacements of gradients. No cap, that’s the whole vibe. periodt ✨

SYNOPSIS

#include <fdhess.h>

Inherits sc::MolecularHessian.

Public Member Functions

• FinDispMolecularHessian (const Ref< MolecularEnergy > &)
• FinDispMolecularHessian (const Ref< KeyVal > &) — The FinDispMolecularHessian KeyVal constructor is used to generate a FinDispMolecularHessian object from the input.
• FinDispMolecularHessian (StateIn &)
• void save_data_state (StateOut &) — Save the base classes (with save_data_state) and the members in the same order that the StateIn CTOR initializes them.
• RefSymmSCMatrix compute_hessian_from_gradients () — These members are used to compute a cartesian hessian from gradients at finite displacements.
• int ndisplace () const
• int ndisplacements_done () const
• RefSCMatrix displacements (int irrep) const
• void displace (int disp)
• void original_geometry ()
• void set_gradient (int disp, const RefSCVector &grad)
• void checkpoint_displacements (StateOut &)
• void restore_displacements (StateIn &)
• RefSymmSCMatrix cartesian_hessian () — This returns the cartesian hessian.
• void set_checkpoint (int c) — Set checkpoint option.
• int checkpoint () const — Return the current value of the checkpoint option.
• void set_energy (const Ref< MolecularEnergy > &energy) — Some MolecularHessian specializations require a molecular energy object.
• MolecularEnergy * energy () const — This returns a MolecularEnergy object, if used by this specialization.
• Ref< SCMatrixKit > matrixkit () const
• RefSCDimension d3natom () const

Protected Member Functions

• void get_disp (int disp, int &irrep, int &index, double &coef)
• void do_hess_for_irrep (int irrep, const RefSymmSCMatrix &dhessian, const RefSymmSCMatrix &xhessian)
• void init ()
• void restart ()

Protected Attributes

• Ref< MolecularEnergy > mole_
• Ref< PointGroup > displacement_point_group_
• Ref< PointGroup > original_point_group_
• RefSCVector original_geometry_
• double disp_
• double accuracy_
• int ndisp_
• int nirrep_
• int restart_
• char * restart_file_
• int checkpoint_
• char * checkpoint_file_
• int only_totally_symmetric_
• int eliminate_cubic_terms_
• int do_null_displacement_
• int debug_
• RefSCMatrix symbasis_
• RefSCVector * gradients_

Additional Inherited Members

This class also has inherited members from its base classes; the original page keeps this heading and doesn’t spell them out here. ✨

Detailed Description

Bestie, this computes the molecular hessian by finite displacements of gradients. It will use the minimum number of displacements, each in the highest possible point group. iconic efficiency 👑

Constructor & Destructor Documentation

sc::FinDispMolecularHessian::FinDispMolecularHessian (const Ref< KeyVal > &)

The FinDispMolecularHessian KeyVal constructor is used to generate a FinDispMolecularHessian object from the input. It reads the keywords below. The original page lays out Keyword / Type / Default / Description, and here is every single one:

• energy — type MolecularEnergy, default none. This gives an object which will be used to compute the gradients needed to form the hessian. If this is not specified, the object using FinDispMolecularHessian will, in some cases, fill it in appropriately. However, even in these cases, it may be desirable to specify this keyword. For example, this could be used in an optimization to compute frequencies using a lower level of theory.
• debug — type boolean, default false. If true, print out debugging information.
• point_group — type PointGroup, default none. The point group to use for generating the displacements.
• restart — type boolean, default true. If true, and a checkpoint file exists, restart from that file.
• restart_file — type string, default basename.ckpt.hess. The name of the file where checkpoint information is written to or read from.
• checkpoint — type boolean, default true. If true, checkpoint intermediate data.
• only_totally_symmetric — type boolean, default false. If true, only follow totally symmetric displacements. The hessian will not be complete, but it has enough information to use it in a geometry optimization.
• eliminate_cubic_terms — type boolean, default true. If true, then cubic terms will be eliminated. This requires that two displacements are done for each totally symmetric coordinate, rather than one. Setting this to false will reduce the accuracy, but the results will still probably be accurate enough for a geometry optimization.
• do_null_displacement — type boolean, default true. Run the calculation at the given geometry as well.
• displacement — type double, default 1.0e-2. The size of the displacement in Bohr.
• gradient_accuracy — type double, default displacement / 1000. The accuracy to which the gradients will be computed.

Member Function Documentation

RefSymmSCMatrix sc::FinDispMolecularHessian::cartesian_hessian () [virtual]

This returns the cartesian hessian. If it has not yet been computed, it will be computed by finite displacements.

Implements sc::MolecularHessian.

MolecularEnergy* sc::FinDispMolecularHessian::energy () const [virtual]

This returns a MolecularEnergy object, if used by this specialization. Otherwise null is returned.

Reimplemented from sc::MolecularHessian.

void sc::FinDispMolecularHessian::save_data_state (StateOut &) [virtual]

Save the base classes (with save_data_state) and the members in the same order that the StateIn CTOR initializes them. This must be implemented by the derived class if the class has data.

Reimplemented from sc::SavableState.

void sc::FinDispMolecularHessian::set_energy (const Ref< MolecularEnergy > &energy) [virtual]

Some MolecularHessian specializations require a molecular energy object. The default implementations of this ignores the argument.

Reimplemented from sc::MolecularHessian.

Author

Generated automatically by Doxygen for MPQC from the source code.

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Catch you later, bestie — this page is from MPQC version 2.3.1, dated Sun Oct 4 2020. slay and stay hydrated 💅✨🫶