from moha.system.hamiltonian.chemical_hamiltonian import *
from moha.system.operator.base import OperatorNames
from moha.posthf.pt.auxiliary import *
from moha.io.log import log, timer
import numpy as np
import copy
__all__ = ['MP2Solver']
[docs]class MP2Solver(object):
"""Second-order Moller-Plesset perturbation solver.
Attributes
----------
ham
Chemical Hamiltonian.
wfn
Hartree Fock wavefunction.
hf_results : dict
Hartree Fock calculation results.
Methods
-------
__init__(self,ham,wfn,hf_results)
Initialize the solver.
kernel(self)
Kernel of the solver.
assign_hamiltonian(self,ham)
Assign the chemical Hamiltonian to the solver.
assign_wavefunction(self,wfn)
Assign the Hartree Fock wavefunction to the solver.
assign_hartree_fock_results(self,hf_results)
Assign the Hartree Fock calculation results to the solver.
"""
def __init__(self,ham,wfn,hf_results):
"""Initialize the solver.
Attributes
----------
ham
Chemical Hamiltonian.
wfn
Hartree Fock wavefunction.
hf_results : dict
Hartree Fock calculation results.
"""
self.assign_hamiltonian(ham)
self.assign_wavefunction(wfn)
self.assign_hartree_fock_results(hf_results)
[docs] @timer.with_section('MP2')
def kernel(self):
"""Kernel of the solver.
Returns
-------
results : dict
MP2 calculation results.
"""
log.hline()
log('MP2 calculation section'.format())
log.hline()
ham = copy.deepcopy(self.ham)
wfn = copy.deepcopy(self.wfn)
hf_results = self.hf_results
nspatial = ham.nspatial
occ = wfn.occ
C = wfn.coefficients
eorbitals = wfn.orbital_energies
Emp2 = 0.0
if isinstance(ham,ChemicalHamiltonian):
Eri = ham.operators[OperatorNames.Eri]
Eri.basis_transformation(C)
for i in range(occ['alpha']):
for j in range(occ['alpha']):
for a in range(occ['alpha'],nspatial):
for b in range(occ['alpha'],nspatial):
Emp2 += Eri[i,a,j,b]*(2*Eri[i,a,j,b]-Eri[i,b,j,a])\
/(eorbitals[i] + eorbitals[j] -eorbitals[a] - eorbitals[b])
log.hline()
log('MP2 Results'.format())
log.hline()
log('{0:2s} {1:3f}'.format('Escf', hf_results['total_energy']))
log('{0:2s} {1:3f}'.format('Emp2', Emp2))
log('{0:2s} {1:3f}'.format('Etot', hf_results['total_energy']+Emp2))
log.hline()
results = {
"success": True,
"mp2_energy":Emp2,
"total_energy":hf_results['total_energy']+Emp2
}
return results
[docs] def assign_hamiltonian(self,ham):
"""Assign the chemical Hamiltonian to the solver.
Attributes
----------
ham
Chemical Hamiltonian.
"""
self.ham = ham
[docs] def assign_wavefunction(self,wfn):
"""Assign the Hartree Fock wavefunction to the solver.
Attributes
----------
wfn
Hartree Fock wavefunction.
"""
self.wfn = wfn
[docs] def assign_hartree_fock_results(self,hf_results):
"""Assign the Hartree Fock calculation results to the solver.
Attributes
----------
hf_results : dict
Hartree Fock calculation results.
Raises
------
TypeError
If Hartree Fock calculation results is not a dictionary.
"""
if not isinstance(hf_results, dict):
raise TypeError("Hartree Fock calculation results must be a dictionary")
self.hf_results = hf_results