Added V2 and ISA support

qiskit_algorithms/custom_types.py

@@ -0,0 +1,27 @@
+# This code is part of a Qiskit project.
+#
+# (C) Copyright IBM 2024.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Types used by the qiskit-algorithms package."""
+
+from typing import Any, List, Protocol, Union
+
+from qiskit import QuantumCircuit
+
+_Circuits = Union[List[QuantumCircuit], QuantumCircuit]
+
+
+class Transpiler(Protocol):
+    """A Generic type to represent a transpiler."""
+
+    def run(self, circuits: _Circuits, **options: Any) -> _Circuits:
+        """Transpile a circuit or a list of quantum circuits."""
+        pass

qiskit_algorithms/phase_estimators/hamiltonian_phase_estimation.py

@@ -1,6 +1,6 @@
 # This code is part of a Qiskit project.
 #
-# (C) Copyright IBM 2020, 2023.
+# (C) Copyright IBM 2020, 2024.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -14,16 +14,16 @@
 
 from __future__ import annotations
 
-
 from qiskit import QuantumCircuit
 from qiskit.circuit.library import PauliEvolutionGate
-from qiskit.primitives import BaseSampler
+from qiskit.primitives import BaseSamplerV2
 from qiskit.quantum_info import SparsePauliOp, Statevector, Pauli
 from qiskit.synthesis import EvolutionSynthesis
 
-from .phase_estimation import PhaseEstimation
 from .hamiltonian_phase_estimation_result import HamiltonianPhaseEstimationResult
+from .phase_estimation import PhaseEstimation
 from .phase_estimation_scale import PhaseEstimationScale
+from ..custom_types import Transpiler
 
 
 class HamiltonianPhaseEstimation:
@@ -83,17 +83,22 @@ class HamiltonianPhaseEstimation:
     def __init__(
         self,
         num_evaluation_qubits: int,
-        sampler: BaseSampler | None = None,
+        sampler: BaseSamplerV2 | None = None,
+        transpiler: Transpiler | None = None,
     ) -> None:
         r"""
         Args:
             num_evaluation_qubits: The number of qubits used in estimating the phase. The phase will
                 be estimated as a binary string with this many bits.
             sampler: The sampler primitive on which the circuit will be sampled.
+            transpiler: An optional object with a `run` method allowing to transpile the circuits
+                that are produced within this algorithm. If set to `None`, these won't be
+                transpiled.
         """
         self._phase_estimation = PhaseEstimation(
             num_evaluation_qubits=num_evaluation_qubits,
             sampler=sampler,
+            transpiler=transpiler,
         )
 
     def _get_scale(self, hamiltonian, bound=None) -> PhaseEstimationScale:

qiskit_algorithms/phase_estimators/ipe.py

@@ -1,6 +1,6 @@
 # This code is part of a Qiskit project.
 #
-# (C) Copyright IBM 2021, 2023.
+# (C) Copyright IBM 2021, 2024.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -19,12 +19,13 @@
 
 from qiskit.circuit import QuantumCircuit, QuantumRegister
 from qiskit.circuit.classicalregister import ClassicalRegister
-from qiskit.primitives import BaseSampler
+from qiskit.primitives import BaseSamplerV2
 
 from qiskit_algorithms.exceptions import AlgorithmError
 
 from .phase_estimator import PhaseEstimator
 from .phase_estimator import PhaseEstimatorResult
+from ..custom_types import Transpiler
 
 
 class IterativePhaseEstimation(PhaseEstimator):
@@ -40,12 +41,16 @@ class IterativePhaseEstimation(PhaseEstimator):
     def __init__(
         self,
         num_iterations: int,
-        sampler: BaseSampler | None = None,
+        sampler: BaseSamplerV2 | None = None,
+        transpiler: Transpiler | None = None,
     ) -> None:
         r"""
         Args:
             num_iterations: The number of iterations (rounds) of the phase estimation to run.
             sampler: The sampler primitive on which the circuit will be sampled.
+            transpiler: An optional object with a `run` method allowing to transpile the circuits
+                that are produced within this algorithm. If set to `None`, these won't be
+                transpiled.
 
         Raises:
             ValueError: if num_iterations is not greater than zero.
@@ -58,6 +63,7 @@ def __init__(
             raise ValueError("`num_iterations` must be greater than zero.")
         self._num_iterations = num_iterations
         self._sampler = sampler
+        self._pass_manager = transpiler
 
     def construct_circuit(
         self,
@@ -125,9 +131,17 @@ def _estimate_phase_iteratively(self, unitary, state_preparation):
             qc = self.construct_circuit(
                 unitary, state_preparation, k, -2 * numpy.pi * omega_coef, True
             )
+
+            if self._pass_manager is not None:
+                qc = self._pass_manager.run(qc)
+
             try:
                 sampler_job = self._sampler.run([qc])
-                result = sampler_job.result().quasi_dists[0]
+                result = sampler_job.result()[0].data.c
+                result = {
+                    label: value / result.num_shots
+                    for label, value in result.get_int_counts().items()
+                }
             except Exception as exc:
                 raise AlgorithmError("The primitive job failed!") from exc
             x = 1 if result.get(1, 0) > result.get(0, 0) else 0

qiskit_algorithms/phase_estimators/phase_estimation.py

@@ -1,6 +1,6 @@
 # This code is part of a Qiskit project.
 #
-# (C) Copyright IBM 2020, 2023.
+# (C) Copyright IBM 2020, 2024.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -20,13 +20,14 @@
 from qiskit import circuit
 from qiskit.circuit import QuantumCircuit
 from qiskit.circuit.classicalregister import ClassicalRegister
-from qiskit.primitives import BaseSampler
+from qiskit.primitives import BaseSamplerV2
 from qiskit.result import Result
 
 from qiskit_algorithms.exceptions import AlgorithmError
 
 from .phase_estimation_result import PhaseEstimationResult, _sort_phases
 from .phase_estimator import PhaseEstimator
+from ..custom_types import Transpiler
 
 
 class PhaseEstimation(PhaseEstimator):
@@ -82,13 +83,17 @@ class PhaseEstimation(PhaseEstimator):
     def __init__(
         self,
         num_evaluation_qubits: int,
-        sampler: BaseSampler | None = None,
+        sampler: BaseSamplerV2 | None = None,
+        transpiler: Transpiler | None = None,
     ) -> None:
         r"""
         Args:
             num_evaluation_qubits: The number of qubits used in estimating the phase. The phase will
                 be estimated as a binary string with this many bits.
             sampler: The sampler primitive on which the circuit will be sampled.
+            transpiler: An optional object with a `run` method allowing to transpile the circuits
+                that are produced within this algorithm. If set to `None`, these won't be
+                transpiled.
 
         Raises:
             AlgorithmError: If a sampler is not provided
@@ -101,6 +106,7 @@ def __init__(
             self._num_evaluation_qubits = num_evaluation_qubits
 
         self._sampler = sampler
+        self._pass_manager = transpiler
 
     def construct_circuit(
         self, unitary: QuantumCircuit, state_preparation: QuantumCircuit | None = None
@@ -189,18 +195,23 @@ def estimate_from_pe_circuit(self, pe_circuit: QuantumCircuit) -> PhaseEstimatio
             AlgorithmError: Primitive job failed.
         """
 
+        if self._pass_manager is not None:
+            pe_circuit = self._pass_manager.run(pe_circuit)
+
         self._add_measurement_if_required(pe_circuit)
 
         try:
             circuit_job = self._sampler.run([pe_circuit])
             circuit_result = circuit_job.result()
         except Exception as exc:
             raise AlgorithmError("The primitive job failed!") from exc
-        phases = circuit_result.quasi_dists[0]
+        phases = circuit_result[0].data.meas.get_counts()
+        # Ensure we still return the measurement strings in sorted order, which SamplerV2 doesn't
+        # guarantee
+        measurement_labels = sorted(phases.keys())
         phases_bitstrings = {}
-        for key, phase in phases.items():
-            bitstring_key = self._get_reversed_bitstring(self._num_evaluation_qubits, key)
-            phases_bitstrings[bitstring_key] = phase
+        for key in measurement_labels:
+            phases_bitstrings[key[::-1]] = phases[key] / circuit_result[0].data.meas.num_shots
         phases = phases_bitstrings
 
         return PhaseEstimationResult(

qiskit_algorithms/phase_estimators/phase_estimator.py

@@ -1,6 +1,6 @@
 # This code is part of a Qiskit project.
 #
-# (C) Copyright IBM 2020, 2023.
+# (C) Copyright IBM 2020, 2024.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -38,10 +38,6 @@ def estimate(
         """Estimate the phase."""
         raise NotImplementedError
 
-    @staticmethod
-    def _get_reversed_bitstring(length: int, number: int) -> str:
-        return f"{number:b}".zfill(length)[::-1]
-
 
 class PhaseEstimatorResult(AlgorithmResult):
     """Phase Estimator Result."""