Adding dimension property to comparison of XPowGate and ZPowGate (#6005)

* adding methods so that dimension is included in _value_equality_values_ and _json_dict_

* quick fix to use canonical exponent in added methods

* needed to update the json for unit tests as well

* fix code style

* updating last jsons to include dimension

* Revert "updating last jsons to include dimension"

This reverts commit 7387710.

* Revert "needed to update the json for unit tests as well"

This reverts commit 473c99e.

* adding dimension to json dict only if dimension is not the default

* adding json and repr files to test XPowGate and ZPowGate dimension

* updating json and repr files to test XPowGate and ZPowGate dimension and removing individual files

* updating _value_equality_values_ function after review and adding _value_equality_approximate_values_ For X and Z PowGates

* removing redundant test for read_json

---------

Co-authored-by: Tanuj Khattar <tanujkhattar@google.com>

cirq-core/cirq/ops/common_gates.py

@@ -120,6 +120,10 @@ def __init__(
         super().__init__(exponent=exponent, global_shift=global_shift)
         self._dimension = dimension
 
+    @property
+    def dimension(self) -> value.TParamVal:
+        return self._dimension
+
     def _num_qubits_(self) -> int:
         return 1
 
@@ -316,6 +320,18 @@ def __repr__(self) -> str:
         all_args = ', '.join(args)
         return f'cirq.XPowGate({all_args})'
 
+    def _json_dict_(self) -> Dict[str, Any]:
+        d = protocols.obj_to_dict_helper(self, ['exponent', 'global_shift'])
+        if self.dimension != 2:
+            d['dimension'] = self.dimension
+        return d
+
+    def _value_equality_values_(self):
+        return (*super()._value_equality_values_(), self._dimension)
+
+    def _value_equality_approximate_values_(self):
+        return (*super()._value_equality_approximate_values_(), self._dimension)
+
 
 class Rx(XPowGate):
     r"""A gate with matrix $e^{-i X t/2}$ that rotates around the X axis of the Bloch sphere by $t$.
@@ -608,6 +624,10 @@ def __init__(
         super().__init__(exponent=exponent, global_shift=global_shift)
         self._dimension = dimension
 
+    @property
+    def dimension(self) -> value.TParamVal:
+        return self._dimension
+
     def _num_qubits_(self) -> int:
         return 1
 
@@ -834,6 +854,18 @@ def _commutes_on_qids_(
             return NotImplemented
         return True
 
+    def _json_dict_(self) -> Dict[str, Any]:
+        d = protocols.obj_to_dict_helper(self, ['exponent', 'global_shift'])
+        if self.dimension != 2:
+            d['dimension'] = self.dimension
+        return d
+
+    def _value_equality_values_(self):
+        return (*super()._value_equality_values_(), self._dimension)
+
+    def _value_equality_approximate_values_(self):
+        return (*super()._value_equality_approximate_values_(), self._dimension)
+
 
 class Rz(ZPowGate):
     r"""A gate with matrix $e^{-i Z t/2}$ that rotates around the Z axis of the Bloch sphere by $t$.

cirq-core/cirq/ops/common_gates_test.py

@@ -1100,6 +1100,7 @@ def test_approx_eq():
 
 def test_xpow_dim_3():
     x = cirq.XPowGate(dimension=3)
+    assert cirq.X != x
     # fmt: off
     expected = [
         [0, 0, 1],
@@ -1127,6 +1128,7 @@ def test_xpow_dim_3():
 
 def test_xpow_dim_4():
     x = cirq.XPowGate(dimension=4)
+    assert cirq.X != x
     # fmt: off
     expected = [
         [0, 0, 0, 1],
@@ -1159,6 +1161,7 @@ def test_zpow_dim_3():
     L = np.exp(2 * np.pi * 1j / 3)
     L2 = L**2
     z = cirq.ZPowGate(dimension=3)
+    assert cirq.Z != z
     # fmt: off
     expected = [
         [1, 0, 0],
@@ -1209,6 +1212,7 @@ def test_zpow_dim_3():
 
 def test_zpow_dim_4():
     z = cirq.ZPowGate(dimension=4)
+    assert cirq.Z != z
     # fmt: off
     expected = [
         [1, 0, 0, 0],

cirq-core/cirq/protocols/json_test_data/XPowGate.json

@@ -1,5 +1,13 @@
-{
-  "cirq_type": "XPowGate",
-  "exponent": 0.123,
-  "global_shift": 0.0
-}
+[
+  {
+    "cirq_type": "XPowGate",
+    "exponent": 0.123,
+    "global_shift": 0.0
+  },
+  {
+    "cirq_type": "XPowGate",
+    "exponent": 0.123,
+    "global_shift": 0.0,
+    "dimension": 3
+  }
+]

cirq-core/cirq/protocols/json_test_data/XPowGate.repr

@@ -1 +1 @@
-(cirq.X**0.123)
+[(cirq.X**0.123), cirq.XPowGate(exponent=0.123, dimension=3)]

cirq-core/cirq/protocols/json_test_data/ZPowGate.json

@@ -1,5 +1,13 @@
-{
-  "cirq_type": "ZPowGate",
-  "exponent": 0.789,
-  "global_shift": 0.0
-}
+[
+  {
+    "cirq_type": "ZPowGate",
+    "exponent": 0.789,
+    "global_shift": 0.0
+  },
+  {
+    "cirq_type": "ZPowGate",
+    "exponent": 0.789,
+    "global_shift": 0.0,
+    "dimension": 3
+  }
+]

cirq-core/cirq/protocols/json_test_data/ZPowGate.repr

@@ -1 +1 @@
-(cirq.Z**0.789)
+[(cirq.Z**0.789), cirq.ZPowGate(exponent=0.789, dimension=3)]