Replace the InitialState components by circuits (qiskit-community/qis…

…kit-aqua#1374)

* make chemistry initial states circuits

* put VSCF circuit in new file

* update several tests

* fix type change to tuple

* merge hf initial state and circuit

* merge initstate+circuit

* update EOH

* update hhl and qaia

* update chc and uvcc

* deprecate InitialState components

* update varformbased test

* fix running tests & mypy

* add reno

* fix iqpe test

* fix variable renaming from merge

* move to circuit.lib and use tuple

- move the initial state circuit to chemistry.circuit.library
- globally replace num_particles by a tuple instead of list of integers

* make _build_bitstr public functions

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

@@ -16,6 +16,7 @@
 import logging
 import numpy as np
 
+from qiskit.circuit import QuantumCircuit
 from qiskit.providers import BaseBackend
 from qiskit.providers import Backend
 from qiskit.aqua import QuantumInstance
@@ -67,7 +68,7 @@ def __init__(self,
                  operator: Union[OperatorBase, LegacyBaseOperator] = None,
                  optimizer: Optimizer = None,
                  p: int = 1,
-                 initial_state: Optional[InitialState] = None,
+                 initial_state: Optional[Union[QuantumCircuit, InitialState]] = None,
                  mixer: Union[OperatorBase, LegacyBaseOperator] = None,
                  initial_point: Optional[np.ndarray] = None,
                  gradient: Optional[Union[GradientBase, Callable[[Union[np.ndarray, List]],

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

@@ -12,10 +12,11 @@
 
 """Global X phases and parameterized problem hamiltonian."""
 
-from typing import Optional
+from typing import Optional, Union
 
 import numpy as np
 
+from qiskit import QuantumCircuit
 from qiskit.aqua.operators import (OperatorBase, X, I, H, CircuitStateFn,
                                    EvolutionFactory, LegacyBaseOperator)
 from qiskit.aqua.components.variational_forms import VariationalForm
@@ -31,7 +32,7 @@ class QAOAVarForm(VariationalForm):
     def __init__(self,
                  cost_operator: OperatorBase,
                  p: int,
-                 initial_state: Optional[InitialState] = None,
+                 initial_state: Optional[Union[QuantumCircuit, InitialState]] = None,
                  mixer_operator: Optional[OperatorBase] = None):
         """
         Constructor, following the QAOA paper https://arxiv.org/abs/1411.4028
@@ -81,9 +82,10 @@ def construct_circuit(self, parameters, q=None):
             ))
 
         # initialize circuit, possibly based on given register/initial state
-        if self._initial_state is not None:
-            stateVector = CircuitStateFn(self._initial_state.construct_circuit('circuit'))
-            circuit = stateVector.to_circuit_op()
+        if isinstance(self._initial_state, QuantumCircuit):
+            circuit = CircuitStateFn(self._initial_state)
+        elif self._initial_state is not None:
+            circuit = CircuitStateFn(self._initial_state.construct_circuit('circuit'))
         else:
             circuit = (H ^ self._num_qubits)
 

qiskit/aqua/operators/legacy/weighted_pauli_operator.py

@@ -1250,7 +1250,7 @@ def two_qubit_reduction(operator, num_particles):
                         "Return the empty operator back.")
             return operator
 
-        if isinstance(num_particles, list):
+        if isinstance(num_particles, (tuple, list)):
             num_alpha = num_particles[0]
             num_beta = num_particles[1]
         else: