.TH "sc::MBPT2" 3 "Sun Oct 4 2020" "Version 2.3.1" "MPQC" \" -*- nroff -*-
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.SH NAME
sc::MBPT2 \- The \fBMBPT2\fP class implements several second-order perturbation theory methods\&.  

.SH SYNOPSIS
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\fC#include <mbpt\&.h>\fP
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Inherits \fBsc::Wavefunction\fP\&.
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Inherited by \fBsc::MBPT2_R12\fP\&.
.SS "Public Member Functions"

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.RI "\fBMBPT2\fP (\fBStateIn\fP &)"
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.RI "\fBMBPT2\fP (const \fBRef\fP< \fBKeyVal\fP > &)"
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.RI "The \fBKeyVal\fP constructor\&. "
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.RI "void \fBsave_data_state\fP (\fBStateOut\fP &)"
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.RI "Save the base classes (with save_data_state) and the members in the same order that the \fBStateIn\fP CTOR initializes them\&. "
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.RI "\fBRef\fP< \fBSCF\fP > \fBref\fP ()"
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.RI "double \fBref_energy\fP ()"
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.RI "double \fBcorr_energy\fP ()"
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.RI "\fBRefSCVector\fP \fBref_energy_gradient\fP ()"
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.RI "\fBRefSCVector\fP \fBcorr_energy_gradient\fP ()"
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.RI "int \fBnelectron\fP ()"
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.RI "Returns the number of electrons\&. "
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.RI "int \fBnfzcore\fP () const"
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.RI "int \fBnfzvirt\fP () const"
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.RI "\fBRefSymmSCMatrix\fP \fBdensity\fP ()"
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.RI "Returns the \fBSO\fP density\&. "
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.RI "int \fBspin_polarized\fP ()"
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.RI "Return 1 if the alpha density is not equal to the beta density\&. "
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.RI "int \fBgradient_implemented\fP () const"
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.RI "int \fBvalue_implemented\fP () const"
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.RI "Information about the availability of values, gradients, and hessians\&. "
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.RI "void \fBsymmetry_changed\fP ()"
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.RI "Call this if you have changed the molecular symmetry of the molecule contained by this \fBMolecularEnergy\fP\&. "
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.RI "void \fBobsolete\fP ()"
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.RI "Marks all results as being out of date\&. "
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.RI "void \fBprint\fP (std::ostream &o=\fBExEnv::out0\fP()) const"
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.RI "Print information about the object\&. "
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.SS "Protected Member Functions"

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.RI "void \fBinit_variables\fP ()"
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.RI "void \fBcompute\fP ()"
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.RI "Recompute at least the results that have compute true and are not already computed\&. "
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.RI "void \fBeigen\fP (\fBRefDiagSCMatrix\fP &vals, \fBRefSCMatrix\fP &vecs, \fBRefDiagSCMatrix\fP &occs)"
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.RI "void \fBcompute_hsos_v1\fP ()"
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.RI "\fBdistsize_t\fP \fBcompute_v2_memory\fP (int ni, int nfuncmax, int nbfme, int nshell, int ndocc, int nsocc, int nvir, int nproc)"
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.RI "void \fBcompute_hsos_v2\fP ()"
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.RI "void \fBcompute_hsos_v2_lb\fP ()"
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.RI "int \fBcompute_cs_batchsize\fP (size_t mem_static, int nocc_act)"
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.RI "\fBdistsize_t\fP \fBcompute_cs_dynamic_memory\fP (int ni, int nocc_act)"
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.RI "int \fBmake_cs_gmat\fP (\fBRefSymmSCMatrix\fP &Gmat, double *DPmat)"
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.RI "int \fBmake_cs_gmat_new\fP (\fBRefSymmSCMatrix\fP &Gmat, const \fBRefSymmSCMatrix\fP &DPmat)"
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.RI "void \fBform_max_dens\fP (double *DPmat, signed char *maxp)"
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.RI "int \fBinit_cs_gmat\fP ()"
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.RI "void \fBdone_cs_gmat\fP ()"
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.RI "int \fBmake_g_d_nor\fP (\fBRefSymmSCMatrix\fP &Gmat, double *DPmat, const double *mgdbuff)"
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.RI "void \fBcs_cphf\fP (double **scf_vector, double *Laj, double *eigval, \fBRefSCMatrix\fP &P2aj)"
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.RI "void \fBs2pdm_contrib\fP (const double *intderbuf, double *PHF, double *P2AO, double **hf_ginter, double **ginter)"
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.RI "void \fBhcore_cs_grad\fP (double *PHF, double *PMP2, double **hf_ginter, double **ginter)"
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.RI "void \fBoverlap_cs_grad\fP (double *WHF, double *WMP2, double **hf_ginter, double **ginter)"
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.RI "void \fBcompute_cs_grad\fP ()"
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.SS "Protected Attributes"

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.RI "\fBRef\fP< \fBSCF\fP > \fBreference_\fP"
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.RI "\fBRef\fP< \fBMemoryGrp\fP > \fBmem\fP"
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.RI "int \fBnfzc\fP"
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.RI "int \fBnfzv\fP"
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.RI "size_t \fBmem_alloc\fP"
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.RI "double \fBcphf_epsilon_\fP"
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.RI "int \fBeliminate_in_gmat_\fP"
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.RI "const double * \fBintbuf_\fP"
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.RI "\fBRef\fP< \fBTwoBodyInt\fP > \fBtbint_\fP"
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.RI "\fBRef\fP< \fBTwoBodyInt\fP > * \fBtbints_\fP"
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.RI "\fBRef\fP< \fBTwoBodyDerivInt\fP > * \fBtbintder_\fP"
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.RI "int \fBnbasis\fP"
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.RI "int \fBnoso\fP"
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.RI "\fBRef\fP< \fBMessageGrp\fP > \fBmsg_\fP"
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.RI "int \fBnvir\fP"
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.RI "int \fBnocc\fP"
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.RI "int \fBnsocc\fP"
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.RI "\fBRef\fP< \fBThreadGrp\fP > \fBthr_\fP"
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.RI "int \fBdynamic_\fP"
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.RI "double \fBprint_percent_\fP"
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.RI "int \fBmax_norb_\fP"
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.RI "int * \fBsymorb_irrep_\fP"
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.RI "int * \fBsymorb_num_\fP"
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.RI "char * \fBmethod_\fP"
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.RI "char * \fBalgorithm_\fP"
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.RI "int \fBdo_d1_\fP"
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.RI "int \fBdo_d2_\fP"
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.RI "int \fBnfuncmax\fP"
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.RI "double \fBhf_energy_\fP"
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.RI "\fBRefSCVector\fP \fBhf_gradient_\fP"
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.RI "double \fBrestart_ecorr_\fP"
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.RI "int \fBrestart_orbital_v1_\fP"
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.RI "int \fBrestart_orbital_memgrp_\fP"
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.SS "Additional Inherited Members"
.SH "Detailed Description"
.PP 
The \fBMBPT2\fP class implements several second-order perturbation theory methods\&. 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "sc::MBPT2::MBPT2 (const \fBRef\fP< \fBKeyVal\fP > &)"

.PP
The \fBKeyVal\fP constructor\&. 
.IP "\fB\fCreference\fP\fP" 1c
This gives the reference wavefunction\&. It must be an object of type \fBCLSCF\fP for closed-shell molecules and \fBHSOSSCF\fP for open-shell molecules\&. The is no default\&.
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.IP "\fB\fCnfzc\fP\fP" 1c
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\&.
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.IP "\fB\fCnfzv\fP\fP" 1c
The number of frozen virtual orbitals\&. The default is 0\&.
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.IP "\fB\fCmemory\fP\fP" 1c
The amount of memory, in bytes, that each processor may use\&.
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.IP "\fB\fCmethod\fP\fP" 1c
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\&.
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.IP "\fB\fCmp\fP\fP" 1c
Use Mo/ller-Plesset perturbation theory\&. This is only valid for closed-shell systems\&. Energies and gradients can be computed with this method\&.
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.IP "\fB\fCopt1\fP\fP" 1c
Use the OPT1 variant of open-shell perturbation theory\&. Only energies can be computed for open-shell systems\&.
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.IP "\fB\fCopt2\fP\fP" 1c
Use the OPT2 variant of open-shell perturbation theory\&. Only energies can be computed for open-shell systems\&.
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.IP "\fB\fCzapt\fP\fP" 1c
Use the ZAPT variant of open-shell perturbation theory\&. Only energies can be computed for open-shell systems\&.
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.IP "\fB\fCalgorithm\fP\fP" 1c
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\&.
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.IP "\fB\fCmemgrp\fP\fP" 1c
Use the distributed shared memory algorithm (which uses a \fBMemoryGrp\fP object)\&. This is only valid for MP2 energies and gradients\&.
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.IP "\fB\fCv1\fP\fP" 1c
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\&.
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.IP "\fB\fCv2\fP\fP" 1c
Use algorithm V2\&. Only energies can be computed\&. The maximum number of processors that can be utilized is the number of shells\&.
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.IP "\fB\fCv2lb\fP\fP" 1c
Use a modified V2 algorithm that may compute more two electron integrals, but may get better load balance on the $O(n_\mathrm{basis}^5)$ 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)\&.
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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)\&.
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.IP "\fB\fCmemorygrp\fP\fP" 1c
A \fBMemoryGrp\fP object is used by the memgrp algorithm\&. If this is not given the program will try to find an appropriate default\&.
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.SH "Member Function Documentation"
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.SS "void sc::MBPT2::compute ()\fC [protected]\fP, \fC [virtual]\fP"

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Recompute at least the results that have compute true and are not already computed\&. This should only be called by \fBResult\fP's members\&. 
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Implements \fBsc::Compute\fP\&.
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Reimplemented in \fBsc::MBPT2_R12\fP\&.
.SS "void sc::MBPT2::obsolete ()\fC [virtual]\fP"

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Marks all results as being out of date\&. Any subsequent access to results will cause \fBCompute::compute()\fP to be called\&. 
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Reimplemented from \fBsc::Compute\fP\&.
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Reimplemented in \fBsc::MBPT2_R12\fP\&.
.SS "void sc::MBPT2::save_data_state (\fBStateOut\fP &)\fC [virtual]\fP"

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Save the base classes (with save_data_state) and the members in the same order that the \fBStateIn\fP CTOR initializes them\&. This must be implemented by the derived class if the class has data\&. 
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Reimplemented from \fBsc::MolecularEnergy\fP\&.
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Reimplemented in \fBsc::MBPT2_R12\fP\&.

.SH "Author"
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Generated automatically by Doxygen for MPQC from the source code\&.