Fix flaky behavior of test_xeb_fidelity (#6337)

pavoljuhas · web-flow · commit aa312bcd1c59 · 2023-11-02T16:08:11.000-07:00
Increase tolerance for fidelities calculated with and without state vector amplitudes. Avoid flaky test failures due to round-off errors. Example: https://github.com/quantumlib/Cirq/actions/runs/6726576064/job/18283075054#step:6:598
diff --git a/cirq-core/cirq/experiments/fidelity_estimation_test.py b/cirq-core/cirq/experiments/fidelity_estimation_test.py
@@ -81,7 +81,7 @@ def test_xeb_fidelity(depolarization, estimator):
         f2 = cirq.xeb_fidelity(
             circuit, bitstrings, qubits, amplitudes=amplitudes, estimator=estimator
         )
-        assert np.abs(f - f2) < 1e-6
+        assert np.abs(f - f2) < 2e-6
 
         fs.append(f)
 

Original file line number	Diff line number	Diff line change
`@@ -81,7 +81,7 @@ def test_xeb_fidelity(depolarization, estimator):`
`81`	`81`	`f2 = cirq.xeb_fidelity(`
`82`	`82`	`circuit, bitstrings, qubits, amplitudes=amplitudes, estimator=estimator`
`83`	`83`	`)`
`84`		`- assert np.abs(f - f2) < 1e-6`
	`84`	`+ assert np.abs(f - f2) < 2e-6`
`85`	`85`
`86`	`86`	`fs.append(f)`
`87`	`87`