Add QuantumInstance/Backend to algorithm init (qiskit-community/qiskit-aqua#874)

* Add QuantumInstance/Backend to algorithm init

* make pylintrc the same as terra's

Author: manoelmarques

qiskit/aqua/algorithms/amplitude_amplifiers/grover.py

@@ -15,15 +15,16 @@
 The Grover's Search algorithm.
 """
 
-from typing import Optional
+from typing import Optional, Union
 import logging
 import operator
 import numpy as np
 
 from qiskit import ClassicalRegister, QuantumCircuit, QuantumRegister
 from qiskit.qasm import pi
+from qiskit.providers import BaseBackend
 
-from qiskit.aqua import AquaError
+from qiskit.aqua import QuantumInstance, AquaError
 from qiskit.aqua.utils import get_subsystem_density_matrix
 from qiskit.aqua.utils.validation import validate_min, validate_in_set
 from qiskit.aqua.algorithms import QuantumAlgorithm
@@ -76,9 +77,12 @@ class Grover(QuantumAlgorithm):
     and be used with Grover algorithm to find a satisfiable assignment.
     """
 
-    def __init__(self, oracle: Oracle, init_state: Optional[InitialState] = None,
-                 incremental: bool = False, num_iterations: int = 1,
-                 mct_mode: str = 'basic') -> None:
+    def __init__(self,
+                 oracle: Oracle, init_state: Optional[InitialState] = None,
+                 incremental: bool = False,
+                 num_iterations: int = 1,
+                 mct_mode: str = 'basic',
+                 quantum_instance: Optional[Union[QuantumInstance, BaseBackend]] = None) -> None:
         r"""
         Args:
             oracle: The oracle component
@@ -98,6 +102,7 @@ def __init__(self, oracle: Oracle, init_state: Optional[InitialState] = None,
                 repeated to amplify the amplitude(s) of the target(s). Has a minimum value of 1.
             mct_mode: Multi-Control Toffoli mode ('basic' | 'basic-dirty-ancilla' |
                 'advanced' | 'noancilla')
+            quantum_instance: Quantum Instance or Backend
 
         Raises:
             AquaError: evaluate_classically() missing from the input oracle
@@ -106,7 +111,7 @@ def __init__(self, oracle: Oracle, init_state: Optional[InitialState] = None,
         validate_in_set('mct_mode', mct_mode,
                         {'basic', 'basic-dirty-ancilla',
                          'advanced', 'noancilla'})
-        super().__init__()
+        super().__init__(quantum_instance)
 
         if not callable(getattr(oracle, "evaluate_classically", None)):
             raise AquaError(

qiskit/aqua/algorithms/factorizers/shor.py

@@ -17,14 +17,16 @@
 Quantum Information and Computation, Vol. 3, No. 2 (2003) pp. 175-185
 """
 
+from typing import Optional, Union
 import math
 import array
 import fractions
 import logging
 import numpy as np
 
 from qiskit import ClassicalRegister, QuantumCircuit, QuantumRegister
-
+from qiskit.providers import BaseBackend
+from qiskit.aqua import QuantumInstance
 from qiskit.aqua.utils.arithmetic import is_power
 from qiskit.aqua.utils import get_subsystem_density_matrix
 from qiskit.aqua.algorithms import QuantumAlgorithm
@@ -54,17 +56,21 @@ class Shor(QuantumAlgorithm):
     See also https://arxiv.org/abs/quant-ph/0205095
     """
 
-    def __init__(self, N: int = 15, a: int = 2) -> None:
+    def __init__(self,
+                 N: int = 15,
+                 a: int = 2,
+                 quantum_instance: Optional[Union[QuantumInstance, BaseBackend]] = None) -> None:
         """
         Args:
             N: The integer to be factored, has a min. value of 3.
             a: A random integer that satisfies a < N and gcd(a, N) = 1, has a min. value of 2.
+            quantum_instance: Quantum Instance or Backend
          Raises:
             ValueError: Invalid input
         """
         validate_min('N', N, 3)
         validate_min('a', a, 2)
-        super().__init__()
+        super().__init__(quantum_instance)
         self._n = None
         self._up_qreg = None
         self._down_qreg = None

qiskit/aqua/algorithms/minimum_eigen_solvers/qaoa/qaoa.py

@@ -14,9 +14,12 @@
 
 """ The Quantum Approximate Optimization Algorithm. """
 
-from typing import List, Callable, Optional
+from typing import List, Callable, Optional, Union
 import logging
 import numpy as np
+
+from qiskit.providers import BaseBackend
+from qiskit.aqua import QuantumInstance
 from qiskit.aqua.operators import BaseOperator
 from qiskit.aqua.components.initial_states import InitialState
 from qiskit.aqua.components.optimizers import Optimizer
@@ -64,7 +67,8 @@ def __init__(self, operator: BaseOperator = None, optimizer: Optimizer = None, p
                  mixer: Optional[BaseOperator] = None, initial_point: Optional[np.ndarray] = None,
                  max_evals_grouped: int = 1, aux_operators: Optional[List[BaseOperator]] = None,
                  callback: Optional[Callable[[int, np.ndarray, float, float], None]] = None,
-                 auto_conversion: bool = True) -> None:
+                 auto_conversion: bool = True,
+                 quantum_instance: Optional[Union[QuantumInstance, BaseBackend]] = None) -> None:
         """
         Args:
             operator: Qubit operator
@@ -101,6 +105,7 @@ def __init__(self, operator: BaseOperator = None, optimizer: Optimizer = None, p
                   :class:`~qiskit.aqua.operators.WeightedPauliOperator`
                 - for *qasm simulator or real backend:*
                   :class:`~qiskit.aqua.operators.TPBGroupedWeightedPauliOperator`
+            quantum_instance: Quantum Instance or Backend
         """
         validate_min('p', p, 1)
 
@@ -112,7 +117,8 @@ def __init__(self, operator: BaseOperator = None, optimizer: Optimizer = None, p
         # will cause the var form to be built
         super().__init__(operator, None, optimizer, initial_point=initial_point,
                          max_evals_grouped=max_evals_grouped, aux_operators=aux_operators,
-                         callback=callback, auto_conversion=auto_conversion)
+                         callback=callback, auto_conversion=auto_conversion,
+                         quantum_instance=quantum_instance)
 
     @VQE.operator.setter
     def operator(self, operator: BaseOperator) -> None:

qiskit/aqua/algorithms/minimum_eigen_solvers/vqe.py

@@ -18,7 +18,7 @@
 See https://arxiv.org/abs/1304.3061
 """
 
-from typing import Optional, List, Callable
+from typing import Optional, List, Callable, Union
 import logging
 import functools
 import warnings
@@ -27,8 +27,8 @@
 import numpy as np
 from qiskit import ClassicalRegister, QuantumCircuit
 from qiskit.circuit import ParameterVector
-
-from qiskit.aqua import AquaError
+from qiskit.providers import BaseBackend
+from qiskit.aqua import QuantumInstance, AquaError
 from qiskit.aqua.operators import (TPBGroupedWeightedPauliOperator, WeightedPauliOperator,
                                    MatrixOperator, op_converter)
 from qiskit.aqua.utils.backend_utils import (is_statevector_backend,
@@ -89,7 +89,8 @@ def __init__(self,
                  max_evals_grouped: int = 1,
                  aux_operators: Optional[List[BaseOperator]] = None,
                  callback: Optional[Callable[[int, np.ndarray, float, float], None]] = None,
-                 auto_conversion: bool = True) -> None:
+                 auto_conversion: bool = True,
+                 quantum_instance: Optional[Union[QuantumInstance, BaseBackend]] = None) -> None:
         """
 
         Args:
@@ -124,6 +125,7 @@ def __init__(self,
                   :class:`~qiskit.aqua.operators.WeightedPauliOperator`
                 - for *qasm simulator or real backend:*
                   :class:`~qiskit.aqua.operators.TPBGroupedWeightedPauliOperator`
+            quantum_instance: Quantum Instance or Backend
         """
         validate_min('max_evals_grouped', max_evals_grouped, 1)
 
@@ -146,7 +148,8 @@ def __init__(self,
         super().__init__(var_form=var_form,
                          optimizer=optimizer,
                          cost_fn=self._energy_evaluation,
-                         initial_point=initial_point)
+                         initial_point=initial_point,
+                         quantum_instance=quantum_instance)
 
         self._in_operator = None
         self._operator = None

qiskit/aqua/algorithms/quantum_algorithm.py

@@ -34,8 +34,11 @@ class QuantumAlgorithm(ABC):
     use an exception if a component of the module is available.
     """
     @abstractmethod
-    def __init__(self) -> None:
+    def __init__(self,
+                 quantum_instance: Optional[Union[QuantumInstance, BaseBackend]]) -> None:
         self._quantum_instance = None
+        if quantum_instance:
+            self.quantum_instance = quantum_instance
 
     @property
     def random(self):

qiskit/aqua/algorithms/vq_algorithm.py

@@ -22,13 +22,15 @@
 overridden to opt-out of this infrastructure but still meet the interface requirements.
 """
 
-from typing import Optional, Callable
+from typing import Optional, Callable, Union
 import time
 import logging
 import warnings
 from abc import abstractmethod
 import numpy as np
 
+from qiskit.providers import BaseBackend
+from qiskit.aqua import QuantumInstance
 from qiskit.aqua.algorithms import AlgorithmResult, QuantumAlgorithm
 from qiskit.aqua.components.optimizers import Optimizer
 from qiskit.aqua.components.variational_forms import VariationalForm
@@ -46,7 +48,8 @@ def __init__(self,
                  var_form: VariationalForm,
                  optimizer: Optimizer,
                  cost_fn: Optional[Callable] = None,
-                 initial_point: Optional[np.ndarray] = None) -> None:
+                 initial_point: Optional[np.ndarray] = None,
+                 quantum_instance: Optional[Union[QuantumInstance, BaseBackend]] = None) -> None:
         """
         Args:
             var_form: An optional parameterized variational form (ansatz).
@@ -55,10 +58,11 @@ def __init__(self,
                 supplied on :meth:`find_minimum`.
             initial_point: An optional initial point (i.e. initial parameter values)
                 for the optimizer.
+            quantum_instance: Quantum Instance or Backend
         Raises:
              ValueError: for invalid input
         """
-        super().__init__()
+        super().__init__(quantum_instance)
 
         self._var_form = var_form
         self._optimizer = optimizer