Refactor AbstractControlValues and it's implementations to fix multiple bugs and improve consistency (#5788)

* Remove stale TODO

* Refactor AbstractControlValues and it's implementations to fix multiple bugs and improve consistency

* Revert unrelate change in consistent_protocols

* Fix tests and update json

* Add more json

* Add a lot more tests to control_values_test.py

* Address feedback from maffoo@

* Fix pylint and mypy errors

* maffoo@ feedback part-2

* Update diagrams and change SumOfProducts API to Collection[Sequence[int]]

Author: tanujkhattar

cirq-core/cirq/ops/control_values.py

@@ -82,29 +82,31 @@ def __init__(
         _validate_sub_object(sub_gate)
         if num_controls is None:
             if control_values is not None:
-                num_controls = len(control_values)
+                num_controls = (
+                    control_values._num_qubits_()
+                    if isinstance(control_values, cv.AbstractControlValues)
+                    else len(control_values)
+                )
             elif control_qid_shape is not None:
                 num_controls = len(control_qid_shape)
             else:
                 num_controls = 1
         if control_values is None:
             control_values = ((1,),) * num_controls
-        if num_controls != len(control_values):
-            raise ValueError('len(control_values) != num_controls')
+
+        # Convert to `cv.ProductOfSums` if input is a tuple of control values for each qubit.
+        if not isinstance(control_values, cv.AbstractControlValues):
+            control_values = cv.ProductOfSums(control_values)
+
+        if num_controls != protocols.num_qubits(control_values):
+            raise ValueError('cirq.num_qubits(control_values) != num_controls')
 
         if control_qid_shape is None:
             control_qid_shape = (2,) * num_controls
         if num_controls != len(control_qid_shape):
             raise ValueError('len(control_qid_shape) != num_controls')
         self._control_qid_shape = tuple(control_qid_shape)
 
-        # Convert to sorted tuples
-        if not isinstance(control_values, cv.AbstractControlValues):
-            control_values = cv.ProductOfSums(
-                tuple(
-                    (val,) if isinstance(val, int) else tuple(sorted(val)) for val in control_values
-                )
-            )
         self._control_values = control_values
 
         # Verify control values not out of bounds
@@ -141,14 +143,11 @@ def _decompose_(self, qubits):
             protocols.has_unitary(self.sub_gate)
             and protocols.num_qubits(self.sub_gate) == 1
             and self._qid_shape_() == (2,) * len(self._qid_shape_())
+            and isinstance(self.control_values, cv.ProductOfSums)
         ):
-            if not isinstance(self.control_values, cv.ProductOfSums):
-                return NotImplemented
             control_qubits = list(qubits[: self.num_controls()])
             invert_ops: List['cirq.Operation'] = []
-            for cvals, cqbit in zip(
-                self.control_values._identifier(), qubits[: self.num_controls()]
-            ):
+            for cvals, cqbit in zip(self.control_values, qubits[: self.num_controls()]):
                 if set(cvals) == {0}:
                     invert_ops.append(common_gates.X(cqbit))
                 elif set(cvals) == {0, 1}:
@@ -271,8 +270,6 @@ def _trace_distance_bound_(self) -> Optional[float]:
     def _circuit_diagram_info_(
         self, args: 'cirq.CircuitDiagramInfoArgs'
     ) -> 'cirq.CircuitDiagramInfo':
-        if not isinstance(self.control_values, cv.ProductOfSums):
-            return NotImplemented
         sub_args = protocols.CircuitDiagramInfoArgs(
             known_qubit_count=(
                 args.known_qubit_count - self.num_controls()
@@ -290,27 +287,20 @@ def _circuit_diagram_info_(
         if sub_info is None:
             return NotImplemented
 
-        def get_symbol(vals):
-            if tuple(vals) == (1,):
-                return '@'
-            return f"({','.join(map(str, vals))})"
+        cv_info = protocols.circuit_diagram_info(self.control_values)
 
         return protocols.CircuitDiagramInfo(
-            wire_symbols=(
-                *(get_symbol(vals) for vals in self.control_values._identifier()),
-                *sub_info.wire_symbols,
-            ),
-            exponent=sub_info.exponent,
+            wire_symbols=(*cv_info.wire_symbols, *sub_info.wire_symbols), exponent=sub_info.exponent
         )
 
     def __str__(self) -> str:
-        return self.control_values.diagram_repr() + str(self.sub_gate)
+        return str(self.control_values) + str(self.sub_gate)
 
     def __repr__(self) -> str:
-        if self.num_controls() == 1 and self.control_values._are_ones():
+        if self.num_controls() == 1 and self.control_values.is_trivial:
             return f'cirq.ControlledGate(sub_gate={self.sub_gate!r})'
 
-        if self.control_values._are_ones() and set(self.control_qid_shape) == {2}:
+        if self.control_values.is_trivial and set(self.control_qid_shape) == {2}:
             return (
                 f'cirq.ControlledGate(sub_gate={self.sub_gate!r}, '
                 f'num_controls={self.num_controls()!r})'
@@ -323,7 +313,7 @@ def __repr__(self) -> str:
 
     def _json_dict_(self) -> Dict[str, Any]:
         return {
-            'control_values': self.control_values._identifier(),
+            'control_values': self.control_values,
             'control_qid_shape': self.control_qid_shape,
             'sub_gate': self.sub_gate,
         }

cirq-core/cirq/ops/control_values_test.py

@@ -20,7 +20,6 @@
 
 import cirq
 from cirq.type_workarounds import NotImplementedType
-from cirq.ops import AbstractControlValues
 
 
 class GateUsingWorkspaceForApplyUnitary(cirq.testing.SingleQubitGate):
@@ -89,14 +88,25 @@ def __str__(self):
 
 C0Y = cirq.ControlledGate(cirq.Y, control_values=[0])
 C0C1H = cirq.ControlledGate(cirq.ControlledGate(cirq.H, control_values=[1]), control_values=[0])
+
+nand_control_values = cirq.SumOfProducts([(0, 1), (1, 0), (1, 1)])
+xor_control_values = cirq.SumOfProducts([[0, 1], [1, 0]], name="xor")
+C_01_10_11H = cirq.ControlledGate(cirq.H, control_values=nand_control_values)
+C_xorH = cirq.ControlledGate(cirq.H, control_values=xor_control_values)
+C0C_xorH = cirq.ControlledGate(C_xorH, control_values=[0])
+
 C0Restricted = cirq.ControlledGate(RestrictedGate(), control_values=[0])
+C_xorRestricted = cirq.ControlledGate(RestrictedGate(), control_values=xor_control_values)
 
 C2Y = cirq.ControlledGate(cirq.Y, control_values=[2], control_qid_shape=(3,))
 C2C2H = cirq.ControlledGate(
     cirq.ControlledGate(cirq.H, control_values=[2], control_qid_shape=(3,)),
     control_values=[2],
     control_qid_shape=(3,),
 )
+C_02_20H = cirq.ControlledGate(
+    cirq.H, control_values=cirq.SumOfProducts([[0, 2], [1, 0]]), control_qid_shape=(2, 3)
+)
 C2Restricted = cirq.ControlledGate(RestrictedGate(), control_values=[2], control_qid_shape=(3,))
 
 
@@ -107,7 +117,7 @@ def test_init():
 
 
 def test_init2():
-    with pytest.raises(ValueError, match=r'len\(control_values\) != num_controls'):
+    with pytest.raises(ValueError, match=r'cirq\.num_qubits\(control_values\) != num_controls'):
         cirq.ControlledGate(cirq.Z, num_controls=1, control_values=(1, 0))
     with pytest.raises(ValueError, match=r'len\(control_qid_shape\) != num_controls'):
         cirq.ControlledGate(cirq.Z, num_controls=1, control_qid_shape=(2, 2))
@@ -125,15 +135,15 @@ def test_init2():
     gate = cirq.ControlledGate(cirq.Z, 1)
     assert gate.sub_gate is cirq.Z
     assert gate.num_controls() == 1
-    assert gate.control_values == ((1,),)
+    assert gate.control_values == cirq.ProductOfSums(((1,),))
     assert gate.control_qid_shape == (2,)
     assert gate.num_qubits() == 2
     assert cirq.qid_shape(gate) == (2, 2)
 
     gate = cirq.ControlledGate(cirq.Z, 2)
     assert gate.sub_gate is cirq.Z
     assert gate.num_controls() == 2
-    assert gate.control_values == ((1,), (1,))
+    assert gate.control_values == cirq.ProductOfSums(((1,), (1,)))
     assert gate.control_qid_shape == (2, 2)
     assert gate.num_qubits() == 3
     assert cirq.qid_shape(gate) == (2, 2, 2)
@@ -143,7 +153,7 @@ def test_init2():
     )
     assert gate.sub_gate is cirq.Z
     assert gate.num_controls() == 7
-    assert gate.control_values == ((1,),) * 7
+    assert gate.control_values == cirq.ProductOfSums(((1,),) * 7)
     assert gate.control_qid_shape == (2,) * 7
     assert gate.num_qubits() == 8
     assert cirq.qid_shape(gate) == (2,) * 8
@@ -162,15 +172,15 @@ def test_init2():
     gate = cirq.ControlledGate(cirq.Z, control_values=(0, (0, 1)))
     assert gate.sub_gate is cirq.Z
     assert gate.num_controls() == 2
-    assert gate.control_values == ((0,), (0, 1))
+    assert gate.control_values == cirq.ProductOfSums(((0,), (0, 1)))
     assert gate.control_qid_shape == (2, 2)
     assert gate.num_qubits() == 3
     assert cirq.qid_shape(gate) == (2, 2, 2)
 
     gate = cirq.ControlledGate(cirq.Z, control_qid_shape=(3, 3))
     assert gate.sub_gate is cirq.Z
     assert gate.num_controls() == 2
-    assert gate.control_values == ((1,), (1,))
+    assert gate.control_values == cirq.ProductOfSums(((1,), (1,)))
     assert gate.control_qid_shape == (3, 3)
     assert gate.num_qubits() == 3
     assert cirq.qid_shape(gate) == (3, 3, 2)
@@ -232,9 +242,15 @@ def test_eq():
     eq.add_equality_group(
         cirq.ControlledGate(cirq.H, control_values=[1, (0, 2)], control_qid_shape=[2, 3]),
         cirq.ControlledGate(cirq.H, control_values=(1, [0, 2]), control_qid_shape=(2, 3)),
+        cirq.ControlledGate(
+            cirq.H, control_values=cirq.SumOfProducts([[1, 0], [1, 2]]), control_qid_shape=(2, 3)
+        ),
     )
     eq.add_equality_group(
-        cirq.ControlledGate(cirq.H, control_values=[(2, 0), 1], control_qid_shape=[3, 2])
+        cirq.ControlledGate(cirq.H, control_values=[(2, 0), 1], control_qid_shape=[3, 2]),
+        cirq.ControlledGate(
+            cirq.H, control_values=cirq.SumOfProducts([[2, 1], [0, 1]]), control_qid_shape=(3, 2)
+        ),
     )
     eq.add_equality_group(
         cirq.ControlledGate(cirq.H, control_values=[1, 0], control_qid_shape=[2, 3]),
@@ -278,18 +294,21 @@ def _has_mixture_(self):
         g.controlled(control_values=[1]),
         g.controlled(control_qid_shape=(2,)),
         cirq.ControlledGate(g, num_controls=1),
+        g.controlled(control_values=cirq.SumOfProducts([[1]])),
     )
     eq.add_equality_group(
         cirq.ControlledGate(g, num_controls=2),
         g.controlled(control_values=[1, 1]),
         g.controlled(control_qid_shape=[2, 2]),
         g.controlled(num_controls=2),
         g.controlled().controlled(),
+        g.controlled(control_values=cirq.SumOfProducts([[1, 1]])),
     )
     eq.add_equality_group(
         cirq.ControlledGate(g, control_values=[0, 1]),
         g.controlled(control_values=[0, 1]),
         g.controlled(control_values=[1]).controlled(control_values=[0]),
+        g.controlled(control_values=cirq.SumOfProducts([[1]])).controlled(control_values=[0]),
     )
     eq.add_equality_group(g.controlled(control_values=[0]).controlled(control_values=[1]))
     eq.add_equality_group(
@@ -350,6 +369,20 @@ def test_unitary():
         atol=1e-8,
     )
 
+    C_xorX = cirq.ControlledGate(cirq.X, control_values=xor_control_values)
+    # fmt: off
+    np.testing.assert_allclose(cirq.unitary(C_xorX), np.array([
+            [1, 0, 0, 0, 0, 0, 0, 0],
+            [0, 1, 0, 0, 0, 0, 0, 0],
+            [0, 0, 0, 1, 0, 0, 0, 0],
+            [0, 0, 1, 0, 0, 0, 0, 0],
+            [0, 0, 0, 0, 0, 1, 0, 0],
+            [0, 0, 0, 0, 1, 0, 0, 0],
+            [0, 0, 0, 0, 0, 0, 1, 0],
+            [0, 0, 0, 0, 0, 0, 0, 1]]
+    ))
+    # fmt: on
+
 
 @pytest.mark.parametrize(
     'gate, should_decompose_to_target',
@@ -380,6 +413,10 @@ def test_unitary():
         (cirq.MatrixGate(cirq.testing.random_unitary(4, random_state=1234)), False),
         (cirq.XX ** sympy.Symbol("s"), True),
         (cirq.CZ ** sympy.Symbol("s"), True),
+        # Non-trivial `cirq.ProductOfSum` controls.
+        (C_01_10_11H, False),
+        (C_xorH, False),
+        (C0C_xorH, False),
     ],
 )
 def test_controlled_gate_is_consistent(gate: cirq.Gate, should_decompose_to_target):
@@ -507,7 +544,7 @@ def _has_unitary_(self):
         return True
 
 
-def test_circuit_diagram():
+def test_circuit_diagram_product_of_sums():
     qubits = cirq.LineQubit.range(3)
     c = cirq.Circuit()
     c.append(cirq.ControlledGate(MultiH(2))(*qubits))
@@ -542,6 +579,35 @@ def test_circuit_diagram():
     )
 
 
+def test_circuit_diagram_sum_of_products():
+    q = cirq.LineQubit.range(4)
+    c = cirq.Circuit(C_xorH.on(*q[:3]), C_01_10_11H.on(*q[:3]), C0C_xorH.on(*q))
+    cirq.testing.assert_has_diagram(
+        c,
+        """
+0: ───@────────@(011)───@(00)───
+      │        │        │
+1: ───@(xor)───@(101)───@(01)───
+      │        │        │
+2: ───H────────H────────@(10)───
+                        │
+3: ─────────────────────H───────
+""",
+    )
+    q = cirq.LineQid.for_qid_shape((2, 3, 2))
+    c = cirq.Circuit(C_02_20H(*q))
+    cirq.testing.assert_has_diagram(
+        c,
+        """
+0 (d=2): ───@(01)───
+            │
+1 (d=3): ───@(20)───
+            │
+2 (d=2): ───H───────
+""",
+    )
+
+
 class MockGate(cirq.testing.TwoQubitGate):
     def _circuit_diagram_info_(self, args: cirq.CircuitDiagramInfoArgs) -> cirq.CircuitDiagramInfo:
         self.captured_diagram_args = args
@@ -571,12 +637,21 @@ def test_bounded_effect():
     assert cirq.trace_distance_bound(cirq.ControlledGate(cirq.X**foo)) == 1
 
 
-def test_repr():
-    cirq.testing.assert_equivalent_repr(cirq.ControlledGate(cirq.Z))
-    cirq.testing.assert_equivalent_repr(cirq.ControlledGate(cirq.Z, num_controls=1))
-    cirq.testing.assert_equivalent_repr(cirq.ControlledGate(cirq.Z, num_controls=2))
-    cirq.testing.assert_equivalent_repr(C0C1H)
-    cirq.testing.assert_equivalent_repr(C2C2H)
+@pytest.mark.parametrize(
+    'gate',
+    [
+        cirq.ControlledGate(cirq.Z),
+        cirq.ControlledGate(cirq.Z, num_controls=1),
+        cirq.ControlledGate(cirq.Z, num_controls=2),
+        C0C1H,
+        C2C2H,
+        C_01_10_11H,
+        C_xorH,
+        C_02_20H,
+    ],
+)
+def test_repr(gate):
+    cirq.testing.assert_equivalent_repr(gate)
 
 
 def test_str():
@@ -597,48 +672,3 @@ def test_controlled_mixture():
     c_yes = cirq.ControlledGate(sub_gate=cirq.phase_flip(0.25), num_controls=1)
     assert cirq.has_mixture(c_yes)
     assert cirq.approx_eq(cirq.mixture(c_yes), [(0.75, np.eye(4)), (0.25, cirq.unitary(cirq.CZ))])
-
-
-class MockControlValues(AbstractControlValues):
-    def __and__(self, other):
-        pass
-
-    def _expand(self):
-        pass
-
-    def diagram_repr(self):
-        pass
-
-    def _number_variables(self):
-        pass
-
-    def __len__(self):
-        return 1
-
-    def _identifier(self):
-        pass
-
-    def __hash__(self):
-        pass
-
-    def __repr__(self):
-        pass
-
-    def validate(self, shapes):
-        pass
-
-    def _are_ones(self):
-        pass
-
-    def _json_dict_(self):
-        pass
-
-
-def test_decompose_applies_only_to_ProductOfSums():
-    g = cirq.ControlledGate(cirq.X, control_values=MockControlValues())
-    assert g._decompose_(None) is NotImplemented
-
-
-def test_circuit_diagram_info_applies_only_to_ProductOfSums():
-    g = cirq.ControlledGate(cirq.X, control_values=MockControlValues())
-    assert g._circuit_diagram_info_(None) is NotImplemented