Backport global phase from Qiskit#5517 on grover operator

This commit adds a missing phase of pi to the grover operator circuit library entry. It is a backport from Qiskit#5517.
mtreinish · Jan 25, 2021 · aa19b72 · aa19b72
1 parent 44092e4
commit aa19b72
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/qiskit/circuit/library/grover_operator.py b/qiskit/circuit/library/grover_operator.py
@@ -256,6 +256,8 @@ def _build(self):
             self.barrier()
         self.compose(self.state_preparation, list(range(self.state_preparation.num_qubits)),
                      inplace=True)
+        # minus sign
+        self.global_phase = numpy.pi
 
 
 # TODO use the oracle compiler or the bit string oracle