feat: added support for power elevation + removed outdated test

qiboteam · Oct 16, 2024 · 2b34b5c · 2b34b5c
1 parent 63b1ce7
commit 2b34b5c
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Showing 3 changed files with 5 additions and 15 deletions.
diff --git a/src/qibo/hamiltonians/hamiltonians.py b/src/qibo/hamiltonians/hamiltonians.py
@@ -585,7 +585,7 @@ def _exp_from_circuit(self, circuit: dict, qubit_map: dict, nshots: int = None):
             )
             measurements = [
                 gates.M(factor.target_qubit, basis=factor.gate.__class__)
-                for factor in term.factors
+                for factor in set(term.factors)
             ]
             circ_copy = circuit.copy(True)
             [circ_copy.add(m) for m in measurements]
@@ -672,9 +672,6 @@ def expectation_from_samples(
         Returns:
             (float) the computed expectation value.
         """
-        for term in self.terms:
-            if len(term.factors) != len(set(term.factors)):
-                raise_error(NotImplementedError, "Z^k is not implemented since Z^2=I.")
 
         if isinstance(data, dict):
             return self._exp_from_freq(data, qubit_map)

diff --git a/tests/test_hamiltonians.py b/tests/test_hamiltonians.py
@@ -264,7 +264,10 @@ def test_hamiltonian_expectation_errors(backend):
 
 @pytest.mark.parametrize(
     "observable",
-    [2 * Z(0) * Z(1) + Z(0) * Z(2), X(0) * Z(1) + Y(0) * X(2) / 2 - Z(0) * Y(1)],
+    [
+        2 * Z(0) * Z(1) ** 2 + Z(0) * Z(2),
+        X(0) * Z(1) + Y(0) * X(2) / 2 - Z(0) * Y(1) ** 3,
+    ],
 )
 def test_hamiltonian_expectation_from_samples(backend, observable):
     """Test Hamiltonian expectation value calculation."""

diff --git a/tests/test_hamiltonians_symbolic.py b/tests/test_hamiltonians_symbolic.py
@@ -330,16 +330,6 @@ def test_hamiltonian_expectation_from_samples(backend):
     backend.assert_allclose(ev0, ev1, atol=20 / np.sqrt(nshots))
 
 
-def test_hamiltonian_expectation_from_samples_errors(backend):
-    obs = [Z(0) * Y(1), Z(0) * Z(1) ** 3]
-    h1 = hamiltonians.SymbolicHamiltonian(obs[0], backend=backend)
-    h2 = hamiltonians.SymbolicHamiltonian(obs[1], backend=backend)
-    with pytest.raises(NotImplementedError):
-        h1.expectation_from_samples(None, qubit_map=None)
-    with pytest.raises(NotImplementedError):
-        h2.expectation_from_samples(None, qubit_map=None)
-
-
 @pytest.mark.parametrize("density_matrix", [False, True])
 @pytest.mark.parametrize("calcterms", [False, True])
 def test_symbolic_hamiltonian_abstract_symbol_ev(backend, density_matrix, calcterms):