Performance improvements for opflow

qiskit/aqua/operators/converters/circuit_sampler.py

@@ -164,12 +164,13 @@ def convert(self,
         Returns:
             The converted Operator with CircuitStateFns replaced by DictStateFns or VectorStateFns.
         """
-        if self._last_op is None or operator != self._last_op:
+        if self._last_op is None or id(operator) != id(self._last_op):
             # Clear caches
             self._last_op = operator
             self._reduced_op_cache = None
             self._circuit_ops_cache = None
             self._transpiled_circ_cache = None
+            self._transpile_before_bind = True
 
         if not self._reduced_op_cache:
             operator_dicts_replaced = operator.to_circuit_op()

qiskit/aqua/operators/primitive_ops/circuit_op.py

@@ -47,7 +47,7 @@ def __init__(self,
             coeff: A coefficient multiplying the primitive
 
         Raises:
-            TypeError: invalid parameters.
+            TypeError: Unsupported primitive, or primitive has ClassicalRegisters.
         """
         if isinstance(primitive, Instruction):
             qc = QuantumCircuit(primitive.num_qubits)
@@ -58,6 +58,9 @@ def __init__(self,
             raise TypeError('CircuitOp can only be instantiated with '
                             'QuantumCircuit, not {}'.format(type(primitive)))
 
+        if len(primitive.clbits) != 0:
+            raise TypeError('CircuitOp does not support QuantumCircuits with ClassicalRegisters.')
+
         super().__init__(primitive, coeff=coeff)
 
     def primitive_strings(self) -> Set[str]:
@@ -122,11 +125,7 @@ def compose(self, other: OperatorBase) -> OperatorBase:
             other = other.to_circuit_op()
 
         if isinstance(other, (CircuitOp, CircuitStateFn)):
-            new_qc = QuantumCircuit(self.num_qubits)
-            new_qc.append(other.to_instruction(), qargs=range(self.num_qubits))
-            new_qc.append(self.to_instruction(), qargs=range(self.num_qubits))
-            # TODO Fix, because converting to dag just to append is nuts
-            new_qc = new_qc.decompose()
+            new_qc = other.primitive.combine(self.primitive)
             if isinstance(other, CircuitStateFn):
                 return CircuitStateFn(new_qc,
                                       is_measurement=other.is_measurement,

qiskit/aqua/operators/state_fns/circuit_state_fn.py

@@ -18,7 +18,7 @@
 from typing import Union, Set
 import numpy as np
 
-from qiskit import QuantumCircuit, BasicAer, execute
+from qiskit import QuantumCircuit, BasicAer, execute, ClassicalRegister
 from qiskit.circuit import Instruction, ParameterExpression
 from qiskit.extensions import Initialize, IGate
 
@@ -46,7 +46,7 @@ def __init__(self,
             is_measurement: Whether the StateFn is a measurement operator.
 
         Raises:
-            TypeError: invalid parameters.
+            TypeError: Unsupported primitive, or primitive has ClassicalRegisters.
         """
         if isinstance(primitive, Instruction):
             qc = QuantumCircuit(primitive.num_qubits)
@@ -57,6 +57,9 @@ def __init__(self,
             raise TypeError('CircuitStateFn can only be instantiated '
                             'with QuantumCircuit, not {}'.format(type(primitive)))
 
+        if len(primitive.clbits) != 0:
+            raise TypeError('CircuitOp does not support QuantumCircuits with ClassicalRegisters.')
+
         super().__init__(primitive, coeff=coeff, is_measurement=is_measurement)
 
     @staticmethod
@@ -294,10 +297,10 @@ def eval(self,
     def to_circuit(self, meas: bool = False) -> QuantumCircuit:
         """ Return QuantumCircuit representing StateFn """
         if meas:
-            qc = QuantumCircuit(self.num_qubits, self.num_qubits)
-            qc.append(self.to_instruction(), qargs=range(self.primitive.num_qubits))
-            qc.measure(qubit=range(self.num_qubits), cbit=range(self.num_qubits))
-            return qc.decompose()
+            meas_qc = self.primitive.copy()
+            meas_qc.add_register(ClassicalRegister(self.num_qubits))
+            meas_qc.measure(qubit=range(self.num_qubits), cbit=range(self.num_qubits))
+            return meas_qc
         else:
             return self.primitive
 

test/aqua/operators/test_pauli_expectation.py

@@ -25,7 +25,7 @@
                                    PauliExpectation, AbelianGrouper,
                                    CircuitSampler)
 
-from qiskit import BasicAer, IBMQ
+from qiskit import BasicAer
 
 
 # pylint: disable=invalid-name
@@ -190,6 +190,7 @@ def test_grouped_pauli_expectation(self):
     @unittest.skip(reason="IBMQ testing not available in general.")
     def test_ibmq_grouped_pauli_expectation(self):
         """ pauli expect op vector state vector test """
+        from qiskit import IBMQ
         p = IBMQ.load_account()
         backend = p.get_backend('ibmq_qasm_simulator')
         paulis_op = ListOp([X, Y, Z, I])

test/aqua/test_vqe.py

@@ -18,7 +18,7 @@
 from test.aqua import QiskitAquaTestCase
 import numpy as np
 from ddt import ddt, unpack, data
-from qiskit import BasicAer, QuantumCircuit, IBMQ
+from qiskit import BasicAer, QuantumCircuit
 from qiskit.circuit import ParameterVector
 
 from qiskit.aqua import QuantumInstance, aqua_globals, AquaError
@@ -259,6 +259,7 @@ def test_vqe_mes(self):
     @unittest.skip(reason="IBMQ testing not available in general.")
     def test_ibmq_vqe(self):
         """ IBMQ VQE Test """
+        from qiskit import IBMQ
         provider = IBMQ.load_account()
         backend = provider.get_backend('ibmq_qasm_simulator')
         var_form = RYRZ(self.qubit_op.num_qubits)