feature: add ECR gate (#14)

* feature: add ECR gate

* spacing

* fix: ECR as DoubleTarget

Co-authored-by: Cody Wang <speller26@gmail.com>

src/braket/ir/jaqcd/__init__.py

@@ -15,6 +15,7 @@
     CV,
     CY,
     CZ,
+    ECR,
     XX,
     XY,
     YY,

src/braket/ir/jaqcd/instructions.py

@@ -602,6 +602,26 @@ class Type(str, Enum):
     type = Type.cz
 
 
+class ECR(DoubleTarget):
+    """
+    An echoed RZX(pi/2) gate.
+
+    Attributes:
+        type (str): The instruction type. default = "ecr". (type) is optional.
+            This should be unique among all instruction types.
+        targets (List[int]): The target qubits.
+            This is a list with two items and all items are int >= 0.
+
+    Examples:
+        >>> ECR(targets=[0, 1])
+    """
+
+    class Type(str, Enum):
+        ecr = "ecr"
+
+    type = Type.ecr
+
+
 class XX(DoubleTarget, Angle):
     """
     The Ising (XX) gate.

src/braket/ir/jaqcd/program_v1.py

@@ -19,6 +19,7 @@
     CV,
     CY,
     CZ,
+    ECR,
     XX,
     XY,
     YY,
@@ -88,6 +89,7 @@
     CV.Type.cv: CV,
     CY.Type.cy: CY,
     CZ.Type.cz: CZ,
+    ECR.Type.ecr: ECR,
     H.Type.h: H,
     I.Type.i: I,
     ISwap.Type.iswap: ISwap,
@@ -169,6 +171,7 @@ class Program(BraketSchemaBase):
         CV,
         CY,
         CZ,
+        ECR,
         Depolarizing,
         GeneralizedAmplitudeDamping,
         Pauli_channel,

test/unit_tests/braket/ir/jaqcd/test_quantum_instructions.py

@@ -27,6 +27,7 @@
     CV,
     CY,
     CZ,
+    ECR,
     XX,
     XY,
     YY,
@@ -113,6 +114,7 @@
     (CV, [SingleTarget, SingleControl], "cv"),
     (CY, [SingleTarget, SingleControl], "cy"),
     (CZ, [SingleTarget, SingleControl], "cz"),
+    (ECR, [DoubleTarget], "ecr"),
     (V, [SingleTarget], "v"),
     (Vi, [SingleTarget], "vi"),
     (XX, [DoubleTarget, Angle], "xx"),