from __future__ import annotations
import numpy as np
import numpy.typing as npt
from mpqp.core.instruction.instruction import Instruction
from mpqp.core.instruction.measurement.pauli_string import (
CommutingTypes,
PauliStringMonomial,
)
[docs]
def find_qubitwise_rotations(group: list[PauliStringMonomial]) -> list[Instruction]:
"""Returns the single qubit rotations to handle multi observables in case of
QWC grouping. This function is used in conjunction with the observables
grouping, it rotates each qubits into the shared eigenbasis of the elements
of the group.
Returns:
A list of single qubit instructions.
"""
result = []
for i, atoms in enumerate(group[0].atoms):
if atoms.label == "I":
all_identity = True
for monomial in group:
all_identity &= monomial.atoms[i].label == "I"
if not all_identity:
for base in monomial.atoms[i].get_basis_change():
result.append(base(i))
break
continue
for base in atoms.get_basis_change():
result.append(base(i))
return result
[docs]
def pauli_grouping_greedy(
monomials: list[PauliStringMonomial], type: CommutingTypes
) -> list[list[PauliStringMonomial]]:
"""Regroups the Pauli operators in parameters into groups of
mutual commuting Pauli operators using a greedy approach.
Args:
monomials: list of Pauli monomials to regroup.
type: the commuting type by which we want to group the Pauli operators.
Returns:
A list of list of Pauli monomials containing the fully commutativity grouping.
Examples:
>>> pauli_grouping_greedy(
... [pI@pX@pX, pY@pY@pZ, pI@pI@pI, -3*pZ@pY@pX, pY@pX@pY, -pZ@pZ@pY, 2*pX@pX@pY],
... CommutingTypes.FULL,
... )
[[pI@pX@pX, pY@pY@pZ, pI@pI@pI], [-3*pZ@pY@pX, -1*pZ@pZ@pY], [pY@pX@pY], [2*pX@pX@pY]]
"""
groups: list[list[PauliStringMonomial]] = []
for monomial in monomials:
added = False
for group in groups:
found = False
for monoms in group:
if monoms.name == monomial.name:
found = True
break
if found:
added = True
break
if all(monomial.commutes_with(m_g, type) for m_g in group):
group.append(monomial)
added = True
break
if not added:
groups.append([monomial])
return groups
[docs]
def pauli_monomial_eigenvalues(monom: PauliStringMonomial) -> npt.NDArray[np.float64]:
result = np.array([1], dtype=np.float64)
for atom in monom.atoms:
result = np.kron(result, atom.eigen_values)
return result # pyright: ignore[reportReturnType]
[docs]
def full_commutation_pauli_grouping_ibm_clique(monomials: list[PauliStringMonomial]):
pass