Unwrap Tensor objects from Qiskit Nature as necessary

.github/workflows/test_development_versions.yml

@@ -32,6 +32,8 @@ jobs:
           python -m pip install --upgrade pip tox
           python -m pip install toml typer
           python tools/extremal-python-dependencies.py pin-dependencies \
+              "qiskit @ git+https://github.com/Qiskit/qiskit.git" \
+              "qiskit-nature @ git+https://github.com/qiskit-community/qiskit-nature.git" \
               "qiskit-ibm-runtime @ git+https://github.com/Qiskit/qiskit-ibm-runtime.git" \
               --inplace
       - name: Modify tox.ini for more thorough check

circuit_knitting/forging/cholesky_decomposition.py

@@ -30,6 +30,10 @@
     to_chemist_ordering,
     to_physicist_ordering,
 )
+from qiskit_nature.second_q.operators.symmetric_two_body import (
+    SymmetricTwoBodyIntegrals,
+    unfold,
+)
 
 from .entanglement_forging_ansatz import EntanglementForgingAnsatz
 from .entanglement_forging_operator import EntanglementForgingOperator
@@ -84,6 +88,10 @@ def cholesky_decomposition(
     eri = to_chemist_ordering(
         problem.hamiltonian.electronic_integrals.two_body.alpha["++--"]
     )
+    if isinstance(hcore, SymmetricTwoBodyIntegrals):
+        hcore = unfold(hcore)
+    if isinstance(eri, SymmetricTwoBodyIntegrals):
+        eri = unfold(eri)
     num_alpha = problem.num_alpha
     if num_alpha is None:
         raise ValueError(

pyproject.toml

@@ -32,7 +32,7 @@ dependencies = [
     "qiskit-aer>=0.12.0",
     "qiskit>=0.44.1",
     "qiskit-algorithms>=0.2.1",
-    "qiskit-nature>=0.6.0, <0.7",
+    "qiskit-nature>=0.6.0",
     "qiskit-ibm-runtime>=0.12.2",
 ]
 

test/forging/test_entanglement_forging_ground_state_solver.py

@@ -29,6 +29,7 @@
 from qiskit_nature.second_q.transformers import ActiveSpaceTransformer
 from qiskit_nature.second_q.formats import get_ao_to_mo_from_qcschema
 from qiskit_nature.second_q.hamiltonians import ElectronicEnergy
+from qiskit_nature.second_q.operators import Tensor
 
 from circuit_knitting.forging import (
     EntanglementForgingAnsatz,
@@ -105,6 +106,10 @@ def test_entanglement_forging_vqe_hydrogen(self):
         problem = driver.to_problem(basis=ElectronicBasis.AO)
         qcschema = driver.to_qcschema()
         mo_coeff = get_ao_to_mo_from_qcschema(qcschema).coefficients.alpha["+-"]
+        if isinstance(mo_coeff, Tensor):
+            # Unwrap the Tensor in Qiskit Nature 0.7 and later
+            # to be compatible with qiskit-nature/pull/1248
+            mo_coeff = mo_coeff.array
 
         # Specify the ansatz and bitstrings
         ansatz = EntanglementForgingAnsatz(

test/forging/test_entanglement_forging_knitter.py

@@ -23,6 +23,7 @@
 from qiskit_nature.second_q.problems import ElectronicStructureProblem, ElectronicBasis
 from qiskit_nature.second_q.hamiltonians import ElectronicEnergy
 from qiskit_nature.second_q.formats import get_ao_to_mo_from_qcschema
+from qiskit_nature.second_q.operators import Tensor
 
 from circuit_knitting.forging import (
     EntanglementForgingAnsatz,
@@ -99,6 +100,10 @@ def test_entanglement_forging_H2(self):
 
         # Specify the decomposition method and get the forged operator
         mo_coeff = get_ao_to_mo_from_qcschema(qcschema).coefficients.alpha["+-"]
+        if isinstance(mo_coeff, Tensor):
+            # Unwrap the Tensor in Qiskit Nature 0.7 and later
+            # to be compatible with qiskit-nature/pull/1248
+            mo_coeff = mo_coeff.array
         hamiltonian_terms, energy_shift = cholesky_decomposition(
             problem, mo_coeff=mo_coeff
         )
@@ -175,6 +180,10 @@ def test_entanglement_forging_H2O(self):  # pylint: disable=too-many-locals
 
         # Specify the decomposition method and get the forged operator
         mo_coeff = get_ao_to_mo_from_qcschema(qcschema).coefficients.alpha["+-"]
+        if isinstance(mo_coeff, Tensor):
+            # Unwrap the Tensor in Qiskit Nature 0.7 and later
+            # to be compatible with qiskit-nature/pull/1248
+            mo_coeff = mo_coeff.array
         hamiltonian_terms, energy_shift = cholesky_decomposition(
             problem, mo_coeff=mo_coeff, orbitals_to_reduce=orbitals_to_reduce
         )