sc::MBPT2_R12 - The MBPT2_R12 class implements several
linear R12 second-order perturbation theory methods.
#include <mbptr12.h>
Inherits sc::MBPT2.
MBPT2_R12 (StateIn &)
MBPT2_R12 (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<
GaussianBasisSet > aux_basis () const
Ref< GaussianBasisSet > vir_basis () const
bool gbc () const
bool ebc () const
LinearR12::ABSMethod abs_method () const
LinearR12::StandardApproximation stdapprox () const
bool spinadapted () const
R12IntEvalInfo::StoreMethod r12ints_method () const
const std::string & r12ints_file () const
double corr_energy ()
double r12_corr_energy ()
RefSymmSCMatrix density ()
Returns the SO density. void obsolete ()
Marks all results as being out of date. int gradient_implemented ()
const
int value_implemented () const
Information about the availability of values, gradients, and hessians. void
print (std::ostream &o=ExEnv::out0()) const
Print information about the object.
void compute ()
Recompute at least the results that have compute true and are not already
computed.
The MBPT2_R12 class implements several linear R12
second-order perturbation theory methods.
The KeyVal constructor.
- gbc
- This boolean specifies whether Generalized Brillouin Condition (GBC) is
assumed to hold. The default is 'true'. This keyword is only valid if
stdapprox=A'. The effect of setting this keyword to true is rather small
-- hence it is not recommended to use this keyword.
- ebc
- This boolean specifies whether Extended Brillouin Condition (EBC) is
assumed to hold. The default is 'true'. This keyword is only valid if
stdapprox=A'. The effect of setting this keyword to true is rather small
-- hence it is not recommended to use this keyword.
- stdapprox
- This gives a string that must take on one of the values below. The default
is A'.
- A
- Use second order Mo?/ller-Plesset perturbation theory with linear R12
terms in standard approximation A (MP2-R12/A). Only energies can be
computed with the MP2-R12/A method.
- A'
- Use second order Mo?/ller-Plesset perturbation theory with linear R12
terms in standard approximation A' (MP2-R12/A'). This will cause MP2-R12/A
energies to be computed also. Only energies can be computed with the
MP2-R12/A' method.
- B
- Use second order Mo?/ller-Plesset perturbation theory with linear R12
terms in standard approximation B. This method is not implemented
yet.
- spinadapted
- This boolean specifies whether to compute spin-adapted or spin-orbital
pair energies. Default is to compute spin-adapted energies.
- aux_basis
- This specifies the auxiliary basis to be used for the resolution of the
identity. Default is to use the same basis as for the orbital
expansion.
- vir_basis
- This specifies the basis to be used for the virtual orbitals. Default is
to use the same basis as for the orbital expansion.
- include_mp1
- This specifies whether to compute MP1 correction to the MP2 and MP2-R12
energies. This option only has effect if vir_basis is not the same as
basis. MP1 correction is a perturbative estimate of the difference between
the HF energy computed in vir_basis and basis. Usually, it is a very poor
estimate -- therefore this keyword should be avoided by non-experts.
Default is false.
- abs_method
- This string specifies whether the old ABS method, introduced by Klopper
and Samson, or the new ABS variant, CABS, introduced by Valeev, should be
used. Valid values are 'ABS' (Klopper and Samson), 'ABS+', 'CABS', and
'CABS+', where the '+' labels a method where the union of OBS and ABS is
used to construct the RI basis. The default is 'ABS'. The default in 2.3.0
and later will be 'CABS+'.
- lindep_tol
- The tolerance used to detect linearly dependent basis functions in the RI
basis set. The precise meaning depends on the orthogonalization method.
The default value is 1e-8.
- r12ints
- This specifies how to store transformed MO integrals. Valid values
are:
- mem-posix
- Store integrals in memory for single-pass situations and in a binary file
on task 0's node using POSIX I/O for multipass situations. posix is
usually less efficient than mpi for distributed parallel multipass
runs since the I/O is performed by one task only. However, this method is
guaranteed to work in all types of environments, hence mem-posix is the
default.
- posix
- Store integrals in a binary file on task 0's node using POSIX I/O. This
method is different from mem-posix in that it forces the integrals out
to disk even if they could be stored in memory. posix should only be
used for benchmarking and testing purposes.
- mem-mpi
- Store integrals in memory for single-pass situations and in a binary file
using MPI-I/O for multipass situations. This method assumes the
availability of MPI-I/O. mem-mpi is the preferred choice in distributed
environments which have MPI-I/O available.
- mpi
- Store integrals in a binary file using MPI-I/O. This method is different
from mem-mpi in that it forces the integrals out to disk even if they
could be stored in memory. mpi should only be used for benchmarking
and testing purposes.
- mem
- Store integrals in memory. Can only be used with single-pass
transformations for MP2-R12/A and MP2-R12/A' methods. This method should
only be used for testing purposes.
If r12ints is not specified, then mem-posix method will be
used. If user wishes to use MPI-I/O, pending its availability, for higher
parallel efficiency, r12ints should be explicitly set to mem-mpi.
- r12ints_file
- This specifies the prefix for the transformed MO integrals file if
r12ints is set to posix, mpi, mem-posix or mem-mpi is
used. Default is './<i>inputbasename</i>.r12ints', where
inputbasename is the name of the input file without '.in'.
If MPI-I/O is used then it is user's responsibility to ensure that the
file resides on a file system that supports MPI-I/O.
- twopdm_grid_aa
- This optional keyword specifies a TwoBodyGrid object which to use
for coordinates at which to compute alpha-alpha part of 2-PDM.
- twopdm_grid_ab
- This optional keyword specifies a TwoBodyGrid object which to use
for coordinates at which to compute alpha-beta part of 2-PDM.
Recompute at least the results that have compute true and are not
already computed. This should only be called by Result's members.
Reimplemented from sc::MBPT2.
Marks all results as being out of date. Any subsequent access to
results will cause Compute::compute() to be called.
Reimplemented from sc::MBPT2.
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::MBPT2.
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