sc::MBPT2(3)

🌸 NAME 🌸

okay so this is sc::MBPT2 from the MPQC manual — the class that implements several second-order perturbation theory methods. It’s giving quantum-chemistry main character energy, and yes bestie, we’re getting into all of it 💅✨

✨ 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• void obsolete () — Marks all results as being out of date.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

yep, this page also has an Additional Inherited Members heading — the original just drops the heading and keeps it moving, no extra list here ✨

💖 DETAILED DESCRIPTION 💖

The MBPT2 class implements several second-order perturbation theory methods. Periodt. That’s the whole vibe, and now we’re gonna walk through the constructor tea 🫖

🌈 CONSTRUCTOR & DESTRUCTOR DOCUMENTATION 🌈

sc::MBPT2::MBPT2 (const Ref< KeyVal > &)

The KeyVal constructor. This is where you pass the setup details, bestie, and every key matters 💅

• reference — This gives the reference wavefunction. It must be an object of type CLSCF for closed-shell molecules and HSOSSCF for open-shell molecules. There is no default — not one, no cap.
• 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). iconic citations, honestly 🔥

• 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 🎀

Generated automatically by Doxygen for MPQC from the source code.

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💖 That’s the whole MPQC sc::MBPT2(3) page, bestie — Version 2.3.1, Sun Oct 4 2020, straight from the source code. Byeee! 💖