# Source code for openqemist.electronic_structure_solvers.electronic_structure_solver

#   Copyright 2019 1QBit
#
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#
#   Unless required by applicable law or agreed to in writing, software
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and

import abc

[docs]class ElectronicStructureSolver(abc.ABC):
"""Sets interface for objects that perform energy estimation of a molecule.

Specifics vary between concrete implementations, but common to all of them
is that after simulate is called, the right internal state is set for the
class so that get_rdm can return the reduced density matrix for the last
run simulation.
"""

def __init__(self):
pass

[docs]    @abc.abstractmethod
def simulate(self, molecule, mean_field=None):
"""Performs the simulation for a molecule.

The mean field is calculated automatically if not passed in by the
calling code.

Args:
molecule (pyscf.gto.Mole): The molecule on which to perform the
simluation.
mean_field (pyscf.scf.RHF): The mean filed of the molecule. Computed
automatically if None is passed in.
"""
pass

[docs]    @abc.abstractmethod
def get_rdm(self):
"""Returns the RDM for the previous simulation.

In a concrete implementation, the simulate function would set the
necessary internal state for the class so that this function can return
the reduced density matrix.

Returns:
(numpy.array, numpy.array): The one- and two-particle RDMs (float64).

Raises:
RuntimeError: If no simulation has been run.
"""
pass