Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
sc::FinDispMolecularHessian(3)	     MPQC	sc::FinDispMolecularHessian(3)

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_

   Additional Inherited	Members
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.

   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.

Version	2.3.1			Tue Sep	21 2021	sc::FinDispMolecularHessian(3)

NAME | SYNOPSIS | Detailed Description | Constructor & Destructor Documentation | Member Function Documentation | Author

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=sc_FinDispMolecularHessian&sektion=3&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help