Fix Pauli.numberofqubits deprecation (#881)

* Fix Pauli.numberofqubits deprecation

qiskit/aqua/operators/common.py

@@ -2,7 +2,7 @@
 
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2019.
+# (C) Copyright IBM 2019, 2020.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -42,7 +42,7 @@ def pauli_measurement(circuit, pauli, qr, cr, barrier=False):
     Returns:
         QuantumCircuit: the original circuit object with post-rotation gate
     """
-    num_qubits = pauli.numberofqubits
+    num_qubits = pauli.num_qubits
     for qubit_idx in range(num_qubits):
         if pauli.x[qubit_idx]:
             if pauli.z[qubit_idx]:
@@ -260,7 +260,7 @@ def evolution_instruction(pauli_list, evo_time, num_time_slices,
     if not isinstance(power, (int, np.int)) or power < 1:
         raise AquaError("power must be an integer and greater or equal to 1.")
 
-    state_registers = QuantumRegister(pauli_list[0][1].numberofqubits)
+    state_registers = QuantumRegister(pauli_list[0][1].num_qubits)
     if controlled:
         inst_name = 'Controlled-Evolution^{}'.format(power)
         ancillary_registers = QuantumRegister(1)
@@ -275,7 +275,7 @@ def evolution_instruction(pauli_list, evo_time, num_time_slices,
     top_xyz_pauli_indices = [-1] * len(pauli_list)
 
     for pauli_idx, pauli in enumerate(reversed(pauli_list)):
-        n_qubits = pauli[1].numberofqubits
+        n_qubits = pauli[1].num_qubits
         # changes bases if necessary
         nontrivial_pauli_indices = []
         for qubit_idx in range(n_qubits):

qiskit/aqua/operators/pauli_graph.py

@@ -2,7 +2,7 @@
 
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2018, 2019.
+# (C) Copyright IBM 2018, 2020.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -45,9 +45,9 @@ def _create_nodes(self, paulis):
         return tuple(pauli_operators), tuple(pauli_weights)  # fix their ordering
 
     def _get_nqbits(self):
-        nqbits = self.nodes[0].numberofqubits
+        nqbits = self.nodes[0].num_qubits
         for i in range(1, len(self.nodes)):
-            assert nqbits == self.nodes[i].numberofqubits, "different number of qubits"
+            assert nqbits == self.nodes[i].num_qubits, "different number of qubits"
         return nqbits
 
     def _create_edges(self):

qiskit/aqua/operators/tpb_grouped_weighted_pauli_operator.py

@@ -2,7 +2,7 @@
 
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2019.
+# (C) Copyright IBM 2019, 2020.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -115,7 +115,7 @@ def unsorted_grouping(cls, weighted_pauli_operator):
         """
         paulis = weighted_pauli_operator.paulis
         temp_paulis = copy.deepcopy(paulis)
-        n = paulis[0][1].numberofqubits
+        n = paulis[0][1].num_qubits
         grouped_paulis = []
         sorted_paulis = []
 

qiskit/aqua/operators/weighted_pauli_operator.py

@@ -115,7 +115,7 @@ def num_qubits(self):
             int: number of qubits
         """
         if not self.is_empty():
-            return self._paulis[0][1].numberofqubits
+            return self._paulis[0][1].num_qubits
         else:
             logger.warning("Operator is empty, Return 0.")
             return 0