Created SumOfProducts subclass of ControlValues (quantumlib#5755)

This class allows the creation of control values that can't be factored into simple products hence solving quantumlib#4512

cirq/__init__.py

@@ -301,6 +301,7 @@
     SQRT_ISWAP_INV,
     SWAP,
     SwapPowGate,
+    SumOfProducts,
     T,
     TaggedOperation,
     ThreeQubitDiagonalGate,

cirq/json_resolver_cache.py

@@ -213,6 +213,7 @@ def _symmetricalqidpair(qids):
         'SqrtIswapTargetGateset': cirq.SqrtIswapTargetGateset,
         'StabilizerStateChForm': cirq.StabilizerStateChForm,
         'StatePreparationChannel': cirq.StatePreparationChannel,
+        'SumOfProducts': cirq.SumOfProducts,
         'SwapPowGate': cirq.SwapPowGate,
         'SympyCondition': cirq.SympyCondition,
         'TaggedOperation': cirq.TaggedOperation,

cirq/ops/__init__.py

@@ -210,4 +210,4 @@
 
 from cirq.ops.state_preparation_channel import StatePreparationChannel
 
-from cirq.ops.control_values import AbstractControlValues, ProductOfSums
+from cirq.ops.control_values import AbstractControlValues, ProductOfSums, SumOfProducts

cirq/ops/common_gates.py

@@ -233,10 +233,17 @@ def controlled(
             A `cirq.ControlledGate` (or `cirq.CXPowGate` if possible) representing
                 `self` controlled by the given control values and qubits.
         """
+        if control_values and 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
+                )
+            )
         result = super().controlled(num_controls, control_values, control_qid_shape)
         if (
             self._global_shift == 0
             and isinstance(result, controlled_gate.ControlledGate)
+            and isinstance(result.control_values, cv.ProductOfSums)
             and result.control_values[-1] == (1,)
             and result.control_qid_shape[-1] == 2
         ):
@@ -680,10 +687,17 @@ def controlled(
             A `cirq.ControlledGate` (or `cirq.CZPowGate` if possible) representing
                 `self` controlled by the given control values and qubits.
         """
+        if control_values and 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
+                )
+            )
         result = super().controlled(num_controls, control_values, control_qid_shape)
         if (
             self._global_shift == 0
             and isinstance(result, controlled_gate.ControlledGate)
+            and isinstance(result.control_values, cv.ProductOfSums)
             and result.control_values[-1] == (1,)
             and result.control_qid_shape[-1] == 2
         ):
@@ -1116,10 +1130,17 @@ def controlled(
             A `cirq.ControlledGate` (or `cirq.CCZPowGate` if possible) representing
                 `self` controlled by the given control values and qubits.
         """
+        if control_values and 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
+                )
+            )
         result = super().controlled(num_controls, control_values, control_qid_shape)
         if (
             self._global_shift == 0
             and isinstance(result, controlled_gate.ControlledGate)
+            and isinstance(result.control_values, cv.ProductOfSums)
             and result.control_values[-1] == (1,)
             and result.control_qid_shape[-1] == 2
         ):
@@ -1315,10 +1336,17 @@ def controlled(
             A `cirq.ControlledGate` (or `cirq.CCXPowGate` if possible) representing
                 `self` controlled by the given control values and qubits.
         """
+        if control_values and 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
+                )
+            )
         result = super().controlled(num_controls, control_values, control_qid_shape)
         if (
             self._global_shift == 0
             and isinstance(result, controlled_gate.ControlledGate)
+            and isinstance(result.control_values, cv.ProductOfSums)
             and result.control_values[-1] == (1,)
             and result.control_qid_shape[-1] == 2
         ):

cirq/ops/control_values.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import abc
-from typing import Union, Tuple, List, TYPE_CHECKING, Any, Dict, Generator, cast, Iterator
+from typing import Union, Tuple, List, TYPE_CHECKING, Any, Dict, Generator, cast, Iterator, Optional
 from dataclasses import dataclass
 
 import itertools
@@ -53,7 +53,7 @@ def _expand(self) -> Iterator[Tuple[int, ...]]:
         """Expands the (possibly compressed) internal representation into a sum of products representation."""  # pylint: disable=line-too-long
 
     @abc.abstractmethod
-    def diagram_repr(self) -> str:
+    def diagram_repr(self, label: Optional[str] = None) -> str:
         """Returns a string representation to be used in circuit diagrams."""
 
     @abc.abstractmethod
@@ -92,12 +92,6 @@ def _are_ones(self) -> bool:
     def _json_dict_(self) -> Dict[str, Any]:
         pass
 
-    @abc.abstractmethod
-    def __getitem__(
-        self, key: Union[slice, int]
-    ) -> Union['AbstractControlValues', Tuple[int, ...]]:
-        pass
-
     def __iter__(self) -> Generator[Tuple[int, ...], None, None]:
         for assignment in self._expand():
             yield assignment
@@ -154,7 +148,9 @@ def validate(self, qid_shapes: Union[Tuple[int, ...], List[int]]) -> None:
     def _are_ones(self) -> bool:
         return frozenset(self._internal_representation) == {(1,)}
 
-    def diagram_repr(self) -> str:
+    def diagram_repr(self, label: Optional[str] = None) -> str:
+        if label:
+            return label
         if self._are_ones():
             return 'C' * self._number_variables()
 
@@ -174,9 +170,117 @@ def __getitem__(
     def _json_dict_(self) -> Dict[str, Any]:
         return {'_internal_representation': self._internal_representation}
 
-    def __and__(self, other: AbstractControlValues) -> 'ProductOfSums':
+    def __and__(self, other: AbstractControlValues) -> AbstractControlValues:
+        if isinstance(other, SumOfProducts):
+            return SumOfProducts(tuple(p for p in self)) & other
         if not isinstance(other, ProductOfSums):
             raise TypeError(
                 f'And operation not supported between types ProductOfSums and {type(other)}'
             )
         return type(self)(self._internal_representation + other._internal_representation)
+
+
+@dataclass(frozen=True, eq=False)
+class SumOfProducts(AbstractControlValues):
+    """Represents control values as a union of n-bit tuples.
+
+    `SumOfProducts` representation describes the control values as a union
+    of n-bit tuples, where each n-bit tuple represents an allowed assignment
+    of bits for which the control should be activated. This expanded
+    representation allows us to create control values combinations which
+    cannot be factored as a `ProductOfSums` representation.
+
+    For example:
+
+    1) `(|00><00| + |11><11|) X + (|01><01| + |10><10|) I` represents an
+        operator which flips the third qubit if the first two qubits
+        are `00` or `11`, and does nothing otherwise.
+        This can be constructed as
+        >>> xor_control_values = cirq.SumOfProducts(((0, 0), (1, 1)))
+        >>> q0, q1, q2 = cirq.LineQubit.range(3)
+        >>> xor_cop = cirq.X(q2).controlled_by(q0, q1, control_values=xor_control_values)
+
+    2) `(|00><00| + |01><01| + |10><10|) X + (|11><11|) I` represents an
+        operators which flips the third qubit if the `nand` of first two
+        qubits is `1` (i.e. first two qubits are either `00`, `01` or `10`),
+        and does nothing otherwise. This can be constructed as:
+
+        >>> nand_control_values = cirq.SumOfProducts(((0, 0), (0, 1), (1, 0)))
+        >>> q0, q1, q2 = cirq.LineQubit.range(3)
+        >>> nan_cop = cirq.X(q2).controlled_by(q0, q1, control_values=nand_control_values)
+    """
+
+    _internal_representation: Tuple[Tuple[int, ...], ...]
+
+    def __post_init__(self):
+        if not len(self._internal_representation):
+            raise ValueError('SumOfProducts can\'t be empty.')
+        num_qubits = len(self._internal_representation[0])
+        for p in self._internal_representation:
+            if len(p) != num_qubits:
+                raise ValueError(
+                    f'size mismatch between different products of {self._internal_representation}'
+                )
+        if len(self._internal_representation) != len(
+            set(map(tuple, self._internal_representation))
+        ):
+            raise ValueError('SumOfProducts can\'t have duplicate products.')
+
+    def _identifier(self) -> Tuple[Tuple[int, ...], ...]:
+        return self._internal_representation
+
+    def _expand(self) -> Iterator[Tuple[int, ...]]:
+        """Returns the combinations tracked by the object."""
+        self = cast('SumOfProducts', self)
+        return iter(self._internal_representation)
+
+    def __repr__(self) -> str:
+        return f'cirq.SumOfProducts({str(self._identifier())})'
+
+    def _number_variables(self) -> int:
+        return len(self._internal_representation[0])
+
+    def __len__(self) -> int:
+        return self._number_variables()
+
+    def __hash__(self) -> int:
+        return hash(self._internal_representation)
+
+    def validate(self, qid_shapes: Union[Tuple[int, ...], List[int]]) -> None:
+        for vals in self._internal_representation:
+            if len(qid_shapes) != len(vals):
+                raise ValueError(
+                    f'number of values in product {vals} doesn\'t  equal number'
+                    f' of qubits(={len(qid_shapes)})'
+                )
+
+            for i, v in enumerate(vals):
+                if not (0 <= v and v < qid_shapes[i]):
+                    raise ValueError(
+                        f'Control values <{v}> in combination {vals} is outside'
+                        f' of range for control qubit number <{i}>.'
+                    )
+
+    def _are_ones(self) -> bool:
+        return frozenset(self._internal_representation) == {(1,) * self._number_variables()}
+
+    def diagram_repr(self, label: Optional[str] = None) -> str:
+        if label:
+            return label
+        return ','.join(map(lambda p: ''.join(map(str, p)), self._internal_representation))
+
+    def _json_dict_(self) -> Dict[str, Any]:
+        return {'_internal_representation': self._internal_representation}
+
+    def __and__(self, other: AbstractControlValues) -> 'SumOfProducts':
+        if isinstance(other, ProductOfSums):
+            other = SumOfProducts(tuple(p for p in other))
+        if not isinstance(other, SumOfProducts):
+            raise TypeError(
+                f'And operation not supported between types SumOfProducts and {type(other)}'
+            )
+        combined = map(
+            lambda p: tuple(itertools.chain(*p)),
+            itertools.product(self._internal_representation, other._internal_representation),
+        )
+        return SumOfProducts(tuple(combined))

cirq/ops/control_values_test.py

@@ -25,22 +25,63 @@ def test_init_productOfSum():
         ((((0, 1), (1, 0))), {(0, 0), (0, 1), (1, 0), (1, 1)}),
     ]
     for control_values, want in tests:
-        print(control_values)
         got = {c for c in cv.ProductOfSums(control_values)}
         eq.add_equality_group(got, want)
 
 
+def test_init_SumOfProducts():
+    eq = cirq.testing.EqualsTester()
+    tests = [
+        (((1,),), {(1,)}),
+        (((0, 1), (1, 0)), {(0, 1), (1, 0)}),  # XOR
+        (((0, 0), (0, 1), (1, 0)), {(0, 0), (0, 1), (1, 0)}),  # NAND
+    ]
+    for control_values, want in tests:
+        got = {c for c in cv.SumOfProducts(control_values)}
+        eq.add_equality_group(got, want)
+
+    with pytest.raises(ValueError):
+        _ = cv.SumOfProducts([])
+
+    # size mismatch
+    with pytest.raises(ValueError):
+        _ = cv.SumOfProducts([[1], [1, 0]])
+
+    # can't have duplicates
+    with pytest.raises(ValueError):
+        _ = cv.SumOfProducts([[1, 0], [0, 1], [1, 0]])
+
+
 def test_and_operation():
     eq = cirq.testing.EqualsTester()
-    originals = [((1,),), ((0, 1), (1,)), (((0, 1), (1, 0)))]
-    for control_values1 in originals:
-        for control_values2 in originals:
+    product_of_sums_data = [((1,),), ((0, 1), (1,)), (((0, 1), (1, 0)))]
+    for control_values1 in product_of_sums_data:
+        for control_values2 in product_of_sums_data:
             control_vals1 = cv.ProductOfSums(control_values1)
             control_vals2 = cv.ProductOfSums(control_values2)
             want = [v1 + v2 for v1 in control_vals1 for v2 in control_vals2]
             got = [c for c in control_vals1 & control_vals2]
             eq.add_equality_group(got, want)
 
+    sum_of_products_data = [((1,),), ((0, 1),), ((0, 0), (0, 1), (1, 0))]
+    eq = cirq.testing.EqualsTester()
+    for control_values1 in sum_of_products_data:
+        for control_values2 in sum_of_products_data:
+            control_vals1 = cv.SumOfProducts(control_values1)
+            control_vals2 = cv.SumOfProducts(control_values2)
+            want = [v1 + v2 for v1 in control_vals1 for v2 in control_vals2]
+            got = [c for c in control_vals1 & control_vals2]
+            eq.add_equality_group(got, want)
+
+    pos = cv.ProductOfSums(((1,), (0,)))
+    sop = cv.SumOfProducts(((1, 0), (0, 1)))
+    assert tuple(p for p in pos & sop) == ((1, 0, 1, 0), (1, 0, 0, 1))
+
+    assert tuple(p for p in sop & pos) == ((1, 0, 1, 0), (0, 1, 1, 0))
+
+    with pytest.raises(TypeError):
+        _ = sop & 1
+
 
 def test_and_supported_types():
     CV = cv.ProductOfSums((1,))
@@ -52,3 +93,49 @@ def test_repr():
     product_of_sums_data = [((1,),), ((0, 1), (1,)), (((0, 1), (1, 0)))]
     for t in map(cv.ProductOfSums, product_of_sums_data):
         cirq.testing.assert_equivalent_repr(t)
+
+    sum_of_products_data = [((1,),), ((0, 1),), ((0, 0), (0, 1), (1, 0))]
+    for t in map(cv.SumOfProducts, sum_of_products_data):
+        cirq.testing.assert_equivalent_repr(t)
+
+
+def test_validate():
+    control_val = cv.SumOfProducts(((1, 2), (0, 1)))
+
+    _ = control_val.validate([2, 3])
+
+    with pytest.raises(ValueError):
+        _ = control_val.validate([2, 2])
+
+    # number of qubits != number of control values.
+    with pytest.raises(ValueError):
+        _ = control_val.validate([2])
+
+
+def test_len():
+    data = [((1,),), ((0, 1),), ((0, 0), (0, 1), (1, 0))]
+    for vals in data:
+        c = cv.SumOfProducts(vals)
+        assert len(c) == len(vals[0])
+
+
+def test_hash():
+    data = [((1,),), ((0, 1),), ((0, 0), (0, 1), (1, 0))]
+    assert len(set(map(hash, map(cv.SumOfProducts, data)))) == 3
+
+
+def test_are_ones():
+    data = [((1,),), ((0, 1),), ((0, 0), (0, 1), (1, 0)), ((1, 1, 1, 1),)]
+    are_ones = [True, False, False]
+    for vals, want in zip(data, are_ones):
+        c = cv.SumOfProducts(vals)
+        assert c._are_ones() == want
+
+
+def test_diagram_repr():
+    c = cv.SumOfProducts(((1, 0), (0, 1)))
+    assert c.diagram_repr() == '10,01'
+
+    assert c.diagram_repr('xor') == 'xor'
+
+    assert cv.ProductOfSums(((1,), (0,))).diagram_repr('10') == '10'

cirq/ops/controlled_gate_test.py

@@ -633,9 +633,6 @@ def _are_ones(self):
     def _json_dict_(self):
         pass
 
-    def __getitem__(self, idx):
-        pass
-
 
 def test_decompose_applies_only_to_ProductOfSums():
     g = cirq.ControlledGate(cirq.X, control_values=MockControlValues())

cirq/protocols/json_test_data/SumOfProducts.json

@@ -0,0 +1,4 @@
+{
+  "_internal_representation": [[1, 0], [1, 2]],
+  "cirq_type": "SumOfProducts"
+}

cirq/protocols/json_test_data/SumOfProducts.repr

@@ -0,0 +1 @@
+cirq.SumOfProducts([[1, 0], [1, 2]])