Ubuntu Manpage: sc::MBPT2 - The MBPT2 class implements several second-order perturbation theory methods.

NAME

       sc::MBPT2 - The MBPT2 class implements several second-order perturbation theory methods.

SYNOPSIS

       #include <mbpt.h>

       Inherits sc::Wavefunction.

       Inherited by sc::MBPT2_R12.

   Public Member Functions
       MBPT2 (StateIn &)
       MBPT2 (const Ref< KeyVal > &)
           The KeyVal constructor.
       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.
       Ref< SCF > ref ()
       double ref_energy ()
       double corr_energy ()
       RefSCVector ref_energy_gradient ()
       RefSCVector corr_energy_gradient ()
       int nelectron ()
           Returns the number of electrons.
       int nfzcore () const
       int nfzvirt () const
       RefSymmSCMatrix density ()
           Returns the SO density.
       int spin_polarized ()
           Return 1 if the alpha density is not equal to the beta density.
       int gradient_implemented () const
       int value_implemented () const
           Information about the availability of values, gradients, and hessians.
       void symmetry_changed ()
           Call this if you have changed the molecular symmetry of the molecule contained by this
           MolecularEnergy.
       void obsolete ()
           Marks all results as being out of date.
       void print (std::ostream &o=ExEnv::out0()) const
           Print information about the object.

   Protected Member Functions
       void init_variables ()
       void compute ()
           Recompute at least the results that have compute true and are not already computed.
       void eigen (RefDiagSCMatrix &vals, RefSCMatrix &vecs, RefDiagSCMatrix &occs)
       void compute_hsos_v1 ()
       distsize_t compute_v2_memory (int ni, int nfuncmax, int nbfme, int nshell, int ndocc, int nsocc, int
           nvir, int nproc)
       void compute_hsos_v2 ()
       void compute_hsos_v2_lb ()
       int compute_cs_batchsize (size_t mem_static, int nocc_act)
       distsize_t compute_cs_dynamic_memory (int ni, int nocc_act)
       int make_cs_gmat (RefSymmSCMatrix &Gmat, double *DPmat)
       int make_cs_gmat_new (RefSymmSCMatrix &Gmat, const RefSymmSCMatrix &DPmat)
       void form_max_dens (double *DPmat, signed char *maxp)
       int init_cs_gmat ()
       void done_cs_gmat ()
       int make_g_d_nor (RefSymmSCMatrix &Gmat, double *DPmat, const double *mgdbuff)
       void cs_cphf (double **scf_vector, double *Laj, double *eigval, RefSCMatrix &P2aj)
       void s2pdm_contrib (const double *intderbuf, double *PHF, double *P2AO, double **hf_ginter, double
           **ginter)
       void hcore_cs_grad (double *PHF, double *PMP2, double **hf_ginter, double **ginter)
       void overlap_cs_grad (double *WHF, double *WMP2, double **hf_ginter, double **ginter)
       void compute_cs_grad ()

   Protected Attributes
       Ref< SCF > reference_
       Ref< MemoryGrp > mem
       int nfzc
       int nfzv
       size_t mem_alloc
       double cphf_epsilon_
       int eliminate_in_gmat_
       const double * intbuf_
       Ref< TwoBodyInt > tbint_
       Ref< TwoBodyInt > * tbints_
       Ref< TwoBodyDerivInt > * tbintder_
       int nbasis
       int noso
       Ref< MessageGrp > msg_
       int nvir
       int nocc
       int nsocc
       Ref< ThreadGrp > thr_
       int dynamic_
       double print_percent_
       int max_norb_
       int * symorb_irrep_
       int * symorb_num_
       char * method_
       char * algorithm_
       int do_d1_
       int do_d2_
       int nfuncmax
       double hf_energy_
       RefSCVector hf_gradient_
       double restart_ecorr_
       int restart_orbital_v1_
       int restart_orbital_memgrp_

   Additional Inherited Members

Detailed Description

       The MBPT2 class implements several second-order perturbation theory methods.

Constructor & Destructor Documentation

sc::MBPT2::MBPT2 (const Ref< KeyVal > &)
The KeyVal constructor.

reference
This gives the reference wavefunction. It must be an object of type CLSCF for closed-shell molecules
and HSOSSCF for open-shell molecules. The is no default.

nfzc
The number of frozen core orbitals. The default is 0. If no atoms have an atomic number greater than
30, then the number of orbitals to be frozen can be automatically determined by specifying nfzc =
auto.

nfzv
The number of frozen virtual orbitals. The default is 0.

memory
The amount of memory, in bytes, that each processor may use.

method
This gives a string that must take on one of the values below. The default is mp for closed-shell
systems and zapt for open-shell systems.

mp Use M/ller-Plesset perturbation theory. This is only valid for closed-shell systems. Energies and
gradients can be computed with this method.

opt1
Use the OPT1 variant of open-shell perturbation theory. Only energies can be computed for open-shell
systems.

opt2
Use the OPT2 variant of open-shell perturbation theory. Only energies can be computed for open-shell
systems.

zapt
Use the ZAPT variant of open-shell perturbation theory. Only energies can be computed for open-shell
systems.

algorithm
This gives a string that must take on one of the values given below. The default is memgrp for
closed-shell systems. For open-shell systems v1 is used for a small number of processors and v2 is
used otherwise.

memgrp
Use the distributed shared memory algorithm (which uses a MemoryGrp object). This is only valid for
MP2 energies and gradients.

v1 Use algorithm V1. Only energies can be computed. The maximum number of processors that can be
utilized is the number of virtual orbitals. This algorithm computes few integrals than the others,
but has higher communication requirements.

v2 Use algorithm V2. Only energies can be computed. The maximum number of processors that can be
utilized is the number of shells.

v2lb
Use a modified V2 algorithm that may compute more two electron integrals, but may get better load
balance on the $O(n_thrm{basis}^5)$ part of the calculation. Only energies can be computed. This is
recommended only for computations involving large molecules (where the transformation is dominant) on
very many processors (approaching the number of shells).

The v1 and v2 algorithms are discussed in Ida M. B. Nielsen and Edward T. Seidl, J. Comp. Chem. 16, 1301
(1995). The memgrp algorithm is discussed in Ida M. B. Nielsen, Chem. Phys. Lett. 255, 210 (1996).

memorygrp
A MemoryGrp object is used by the memgrp algorithm. If this is not given the program will try to find
an appropriate default.

Member Function Documentation

   void sc::MBPT2::compute () [protected],  [virtual]
       Recompute at least the results that have compute true and are not already computed. This should  only  be
       called by Result's members.

       Implements sc::Compute.

       Reimplemented in sc::MBPT2_R12.

   void sc::MBPT2::obsolete () [virtual]
       Marks all results as being out of date. Any subsequent access to results will cause Compute::compute() to
       be called.

       Reimplemented from sc::Compute.

       Reimplemented in sc::MBPT2_R12.

   void sc::MBPT2::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::MolecularEnergy.

       Reimplemented in sc::MBPT2_R12.

Author

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Version 2.3.1                                    Sun Oct 4 2020                                     sc::MBPT2(3)