Revert "Moving up some parameter checks in the class hierarchy (#3668)…

…" (#4117)

This change has some unforseen backwards compatibility implications and
is causing downstream projects like qiskit-aer to fail CI now. Given the
pending release and this not being critical, this commit reverts this
commit and we can revisit it after the 0.13.0 release.

This reverts commit 5afe87c.

qiskit/circuit/gate.py

@@ -17,7 +17,6 @@
 import numpy as np
 from scipy.linalg import schur
 
-from qiskit.circuit.parameter import ParameterExpression
 from qiskit.circuit.exceptions import CircuitError
 from .instruction import Instruction
 
@@ -220,11 +219,3 @@ def broadcast_arguments(self, qargs, cargs):
             return Gate._broadcast_3_or_more_args(qargs)
         else:
             raise CircuitError('This gate cannot handle %i arguments' % len(qargs))
-
-    def validate_parameter(self, parameter):
-        """Gate parameters should be int, float, or ParameterExpression"""
-        if isinstance(parameter, (int, float, np.number, ParameterExpression)):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} for gate {1}".format(type(parameter),
-                                                                            self.name))

qiskit/circuit/instruction.py

@@ -137,11 +137,29 @@ def params(self):
     def params(self, parameters):
         self._params = []
         for single_param in parameters:
-            self._params.append(self.validate_parameter(single_param))
-
-    def validate_parameter(self, parameter):
-        """Instruction parameters has no validation or normalization."""
-        return parameter
+            # example: u2(pi/2, sin(pi/4))
+            if isinstance(single_param, (ParameterExpression)):
+                self._params.append(single_param)
+            # example: u3(0.1, 0.2, 0.3)
+            elif isinstance(single_param, (int, float)):
+                self._params.append(single_param)
+            # example: Initialize([complex(0,1), complex(0,0)])
+            elif isinstance(single_param, complex):
+                self._params.append(single_param)
+            # example: snapshot('label')
+            elif isinstance(single_param, str):
+                self._params.append(single_param)
+            # example: Aer expectation_value_snapshot [complex, 'X']
+            elif isinstance(single_param, list):
+                self._params.append(single_param)
+            # example: numpy.array([[1, 0], [0, 1]])
+            elif isinstance(single_param, numpy.ndarray):
+                self._params.append(single_param)
+            elif isinstance(single_param, numpy.number):
+                self._params.append(single_param.item())
+            else:
+                raise CircuitError("invalid param type {0} in instruction "
+                                   "{1}".format(type(single_param), self.name))
 
     def is_parameterized(self):
         """Return True .IFF. instruction is parameterized else False"""

qiskit/converters/ast_to_dag.py

@@ -23,6 +23,7 @@
 
 from qiskit.circuit import QuantumRegister, ClassicalRegister, Gate
 from qiskit.qasm.node.real import Real
+from qiskit.circuit.instruction import Instruction
 from qiskit.circuit.measure import Measure
 from qiskit.circuit.reset import Reset
 from qiskit.extensions.standard.barrier import Barrier
@@ -401,9 +402,15 @@ def _create_op(self, name, params):
         if name in self.standard_extension:
             op = self.standard_extension[name](*params)
         elif name in self.gates:
-            op = Gate(name=name, num_qubits=self.gates[name]['n_bits'], params=params)
-            if not self.gates[name]['opaque']:
-                # call a custom gate (otherwise, opaque)
+            if self.gates[name]['opaque']:
+                # call an opaque gate
+                op = Gate(name=name, num_qubits=self.gates[name]['n_bits'], params=params)
+            else:
+                # call a custom gate
+                op = Instruction(name=name,
+                                 num_qubits=self.gates[name]['n_bits'],
+                                 num_clbits=0,
+                                 params=params)
                 op.definition = self._gate_definition_to_qiskit_definition(self.gates[name],
                                                                            params=params)
         else:

qiskit/extensions/quantum_initializer/diagonal.py

@@ -79,13 +79,6 @@ def _define(self):
         diag_circuit.append(gate, q[:])
         self.definition = diag_circuit.data
 
-    def validate_parameter(self, parameter):
-        """Diagonal Gate parameter can be complex in addition to the Gate parameter types."""
-        if isinstance(parameter, complex):
-            return parameter
-        else:
-            return super().validate_parameter(parameter)
-
     def _dec_diag(self):
         """
         Call to create a circuit implementing the diagonal gate.

qiskit/extensions/quantum_initializer/initializer.py

@@ -23,7 +23,6 @@
 from qiskit.circuit import QuantumCircuit
 from qiskit.circuit import QuantumRegister
 from qiskit.circuit import Instruction
-from qiskit.circuit.exceptions import CircuitError
 from qiskit.extensions.standard.x import CXGate
 from qiskit.extensions.standard.ry import RYGate
 from qiskit.extensions.standard.rz import RZGate
@@ -247,14 +246,6 @@ def broadcast_arguments(self, qargs, cargs):
                               (2**self.num_qubits, self.num_qubits, len(flat_qargs)))
         yield flat_qargs, []
 
-    def validate_parameter(self, parameter):
-        """Initialize instruction parameter can be int, float, and complex."""
-        if isinstance(parameter, (int, float, complex)):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} for instruction  "
-                               "{1}".format(type(parameter), self.name))
-
 
 def initialize(self, params, qubits):
     """Apply initialize to circuit."""

qiskit/extensions/quantum_initializer/isometry.py

@@ -28,7 +28,6 @@
 from qiskit import QuantumRegister
 from qiskit.circuit import Instruction
 from qiskit.circuit import QuantumCircuit
-from qiskit.circuit.exceptions import CircuitError
 from qiskit.exceptions import QiskitError
 from qiskit.quantum_info.operators.predicates import is_isometry
 from qiskit.extensions.quantum_initializer.uc import UCGate
@@ -258,14 +257,6 @@ def _define_qubit_role(self, q):
         q_ancillas_dirty = q[n + self.num_ancillas_zero:]
         return q_input, q_ancillas_for_output, q_ancillas_zero, q_ancillas_dirty
 
-    def validate_parameter(self, parameter):
-        """Isometry parameter has to be an ndarray."""
-        if isinstance(parameter, np.ndarray):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} for gate  "
-                               "{1}".format(type(parameter), self.name))
-
 
 # Find special unitary matrix that maps [c0,c1] to [r,0] or [0,r] if basis_state=0 or
 # basis_state=1 respectively

qiskit/extensions/quantum_initializer/mcg_up_to_diagonal.py

@@ -29,7 +29,6 @@
 from qiskit.circuit.quantumcircuit import QuantumRegister, QuantumCircuit
 from qiskit.quantum_info.operators.predicates import is_isometry
 from qiskit.exceptions import QiskitError
-from qiskit.circuit.exceptions import CircuitError
 from qiskit.extensions.quantum_initializer.uc import UCGate
 
 _EPS = 1e-10  # global variable used to chop very small numbers to zero
@@ -117,11 +116,3 @@ def _define_qubit_role(self, q):
         q_ancillas_zero = q[self.num_controls + 1:self.num_controls + 1 + self.num_ancillas_zero]
         q_ancillas_dirty = q[self.num_controls + 1 + self.num_ancillas_zero:]
         return q_target, q_controls, q_ancillas_zero, q_ancillas_dirty
-
-    def validate_parameter(self, parameter):
-        """Multi controlled single-qubit unitary gate parameter has to be an ndarray."""
-        if isinstance(parameter, np.ndarray):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} in gate "
-                               "{1}".format(type(parameter), self.name))

qiskit/extensions/quantum_initializer/squ.py

@@ -29,7 +29,6 @@
 
 from qiskit.circuit import Gate
 from qiskit.circuit.quantumcircuit import QuantumRegister, QuantumCircuit, Qubit
-from qiskit.circuit.exceptions import CircuitError
 from qiskit.quantum_info.operators.predicates import is_unitary_matrix
 from qiskit.exceptions import QiskitError
 
@@ -133,14 +132,6 @@ def _zyz_dec(self):
         # Therefore, we have to take the inverse of the angles at the end.
         return -a, -b, -c, d
 
-    def validate_parameter(self, parameter):
-        """Single-qubit unitary gate parameter has to be an ndarray."""
-        if isinstance(parameter, np.ndarray):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} in gate "
-                               "{1}".format(type(parameter), self.name))
-
 
 def squ(self, u, qubit, mode="ZYZ", up_to_diagonal=False):
     """ Decompose an arbitrary 2*2 unitary into three rotation gates :math:`U=R_zR_yR_z`.

qiskit/extensions/quantum_initializer/uc.py

@@ -46,7 +46,6 @@
 from qiskit.quantum_info.operators.predicates import is_unitary_matrix
 from qiskit.circuit.quantumregister import QuantumRegister
 from qiskit.circuit.quantumcircuit import QuantumCircuit
-from qiskit.circuit.exceptions import CircuitError
 from qiskit.exceptions import QiskitError
 from qiskit.quantum_info.synthesis import OneQubitEulerDecomposer
 
@@ -264,14 +263,6 @@ def _ct(m):
     def _rz(alpha):
         return np.array([[np.exp(1j * alpha / 2), 0], [0, np.exp(-1j * alpha / 2)]])
 
-    def validate_parameter(self, parameter):
-        """Uniformly controlled gate parameter has to be an ndarray."""
-        if isinstance(parameter, np.ndarray):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} in gate "
-                               "{1}".format(type(parameter), self.name))
-
 
 def uc(self, gate_list, q_controls, q_target, up_to_diagonal=False):
     """Attach a uniformly controlled gates (also called multiplexed gates) to a circuit.

qiskit/extensions/standard/barrier.py

@@ -19,7 +19,6 @@
 from qiskit.circuit.quantumregister import QuantumRegister
 from qiskit.circuit import Instruction
 from qiskit.exceptions import QiskitError
-from qiskit.circuit.exceptions import CircuitError
 
 
 class Barrier(Instruction):
@@ -39,10 +38,6 @@ def broadcast_arguments(self, qargs, cargs):
     def c_if(self, classical, val):
         raise QiskitError('Barriers are compiler directives and cannot be conditional.')
 
-    def validate_parameter(self, parameter):
-        """Barrier paramenter"""
-        raise CircuitError("Barrier has no parameters: {0} was provided".format(type(parameter)))
-
 
 def barrier(self, *qargs):
     """Apply barrier to circuit.

qiskit/extensions/unitary.py

@@ -23,7 +23,6 @@
 from qiskit.circuit import QuantumCircuit
 from qiskit.circuit import QuantumRegister
 from qiskit.exceptions import QiskitError
-from qiskit.circuit.exceptions import CircuitError
 from qiskit.extensions.standard import U3Gate
 from qiskit.quantum_info.operators.predicates import matrix_equal
 from qiskit.quantum_info.operators.predicates import is_unitary_matrix
@@ -182,14 +181,6 @@ def qasm(self):
 
         return self._qasm_definition + self._qasmif(self._qasm_name)
 
-    def validate_parameter(self, parameter):
-        """Unitary gate parameter has to be an ndarray."""
-        if isinstance(parameter, numpy.ndarray):
-            return parameter
-        else:
-            raise CircuitError("invalid param type {0} in gate "
-                               "{1}".format(type(parameter), self.name))
-
 
 def _compute_control_matrix(base_mat, num_ctrl_qubits, ctrl_state=None):
     r"""
@@ -228,6 +219,8 @@ def _compute_control_matrix(base_mat, num_ctrl_qubits, ctrl_state=None):
             raise QiskitError('Invalid control state value specified.')
     else:
         raise QiskitError('Invalid control state type specified.')
+    full_mat_dim = ctrl_dim * base_mat.shape[0]
+    full_mat = numpy.zeros((full_mat_dim, full_mat_dim), dtype=base_mat.dtype)
     ctrl_proj = numpy.diag(numpy.roll(ctrl_grnd, ctrl_state))
     full_mat = (numpy.kron(numpy.eye(2**num_target),
                            numpy.eye(ctrl_dim) - ctrl_proj)

test/python/circuit/test_extensions_standard.py

@@ -32,7 +32,7 @@
     HGate, CHGate, IGate, RGate, RXGate, CRXGate, RYGate, CRYGate, RZGate,
     CRZGate, SGate, SdgGate, CSwapGate, TGate, TdgGate, U1Gate, CU1Gate,
     U2Gate, U3Gate, CU3Gate, XGate, CXGate, CCXGate, YGate, CYGate,
-    ZGate, CZGate, Barrier
+    ZGate, CZGate
 )
 
 
@@ -66,11 +66,6 @@ def test_barrier_invalid(self):
         self.assertRaises(CircuitError, qc.barrier, (self.qr, 'a'))
         self.assertRaises(CircuitError, qc.barrier, .0)
 
-    def test_barrier_parameters(self):
-        barrier = Barrier(2)
-        with self.assertRaises(CircuitError):
-            barrier.params = [0, 1]
-
     def test_conditional_barrier_invalid(self):
         qc = self.circuit
         barrier = qc.barrier(self.qr)

test/python/visualization/test_circuit_text_drawer.py

@@ -921,7 +921,6 @@ def test_kraus(self):
 
         self.assertEqual(str(_text_circuit_drawer(qc)), expected)
 
-    @unittest.skip("Add back when Multiplexer is implemented in terms of UCGate")
     def test_multiplexer(self):
         """ Test Multiplexer.
         See https://github.com/Qiskit/qiskit-terra/pull/2238#issuecomment-487630014"""
@@ -1476,7 +1475,6 @@ def test_conditional_reset(self):
 
         self.assertEqual(str(_text_circuit_drawer(circuit)), expected)
 
-    @unittest.skip("Add back when Multiplexer is implemented in terms of UCGate")
     def test_conditional_multiplexer(self):
         """ Test Multiplexer."""
         cx_multiplexer = Gate('multiplexer', 2, [numpy.eye(2), numpy.array([[0, 1], [1, 0]])])