Remove deprecated calls in examples/bcs_mean_field (quantumlib#5737)

- This example was calling optimize_for_xmon
- Use optimze_for_target_gateset instead.

Author: dstrain115

examples/bcs_mean_field.py

@@ -136,7 +136,6 @@
 import numpy as np
 import scipy.optimize
 import cirq
-import cirq_google
 
 
 def main():
@@ -166,7 +165,7 @@ def main():
     bog_circuit = cirq.Circuit(
         bogoliubov_trans(upper_qubits[i], lower_qubits[i], bog_theta[i]) for i in range(n_site)
     )
-    bog_circuit = cirq_google.optimized_for_xmon(bog_circuit)
+    bog_circuit = cirq.optimize_for_target_gateset(bog_circuit, gateset=cirq.CZTargetGateset())
     print('Circuit for the Bogoliubov transformation:')
     print(bog_circuit.to_text_diagram(transpose=True), '\n')
 
@@ -175,15 +174,19 @@ def main():
     fourier_circuit_spin_up = cirq.Circuit(
         fermi_fourier_trans_inverse_4(upper_qubits), strategy=cirq.InsertStrategy.EARLIEST
     )
-    fourier_circuit_spin_up = cirq_google.optimized_for_xmon(fourier_circuit_spin_up)
+    fourier_circuit_spin_up = cirq.optimize_for_target_gateset(
+        fourier_circuit_spin_up, gateset=cirq.CZTargetGateset()
+    )
     print(fourier_circuit_spin_up.to_text_diagram(transpose=True), '\n')
 
     # The inverse fermionic Fourier transformation on the spin-down states
     print(('Circuit for the inverse fermionic Fourier transformation on the spin-down states:'))
     fourier_circuit_spin_down = cirq.Circuit(
         fermi_fourier_trans_inverse_conjugate_4(lower_qubits), strategy=cirq.InsertStrategy.EARLIEST
     )
-    fourier_circuit_spin_down = cirq_google.optimized_for_xmon(fourier_circuit_spin_down)
+    fourier_circuit_spin_down = cirq.optimize_for_target_gateset(
+        fourier_circuit_spin_down, gateset=cirq.CZTargetGateset()
+    )
     print(fourier_circuit_spin_down.to_text_diagram(transpose=True))
 
 

examples/examples_test.py

@@ -69,11 +69,7 @@ def test_example_runs_quantum_fourier_transform():
 
 
 def test_example_runs_bcs_mean_field():
-    pytest.importorskip("cirq_google")
-    with cirq.testing.assert_deprecated(
-        'Use cirq.optimize_for_target_gateset', deadline='v0.16', count=None
-    ):
-        examples.bcs_mean_field.main()
+    examples.bcs_mean_field.main()
 
 
 def test_example_runs_grover():