NAME
sc::FinDispMolecularHessian -
Computes the molecular hessian by finite displacements of gradients.
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_
Detailed Description
Computes the molecular hessian by finite displacements of gradients.
This will use the minimum number of displacements, each in the highest
possible point group.
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.
KeywordTypeDefaultDescription
energyMolecularEnergynoneThis 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.
debugbooleanfalseIf true, print out debugging information.
point_groupPointGroupnoneThe point group to use for generating the
displacements.
restartbooleantrueIf true, and a checkpoint file exists, restart from
that file.
restart_filestring basename.ckpt.hessThe name of the file where
checkpoint information is written to or read from.
checkpointbooleantrueIf true, checkpoint intermediate data.
only_totally_symmetricbooleanfalse If true, only follow totally
symmetric displacments. The hessian will not be complete, but it has
enough information to use it in a geometry optimization.
eliminate_cubic_termsbooleantrueIf 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_displacementbooleantrueRun the calculation at the given
geometry as well.
displacementdouble1.0e-2The size of the displacement in Bohr.
gradient_accuracydoubledisplacement / 1000The 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.
RefSymmSCMatrix sc::FinDispMolecularHessian::compute_hessian_from_gradients
()
These members are used to compute a cartesian hessian from gradients at
finite displacements.
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::MolecularHessian.
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
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