Add decomposition for gates.CRY

src/qibo/gates/gates.py

@@ -1384,6 +1384,14 @@ def __init__(self, q0, q1, theta, trainable=True):
     def qasm_label(self):
         return "cry"
 
+    def decompose(self) -> List[Gate]:
+        """Decomposition of :math:`\\text{CRY}` gate."""
+        from qibo.transpiler.decompositions import (  # pylint: disable=C0415
+            standard_decompositions,
+        )
+
+        return standard_decompositions(self)
+
 
 class CRZ(_CRn_):
     """Controlled rotation around the Z-axis for the Bloch sphere.

src/qibo/transpiler/decompositions.py

@@ -493,6 +493,16 @@ def _decomposition_generalized_RBS(ins, outs, theta, phi, controls):
 standard_decompositions.add(
     gates.CSXDG, [gates.H(1), gates.CU1(0, 1, -np.pi / 2), gates.H(1)]
 )
+standard_decompositions.add(
+    gates.CRY,
+    lambda gate: [
+        gates.RY(1, gate.parameters[0] / 4),
+        gates.CNOT(0, 1),
+        gates.RY(1, -gate.parameters[0] / 2),
+        gates.CNOT(0, 1),
+        gates.RY(1, gate.parameters[0] / 4),
+    ],
+)
 standard_decompositions.add(
     gates.RZX,
     lambda gate: [

tests/test_gates_gates.py

@@ -698,6 +698,9 @@ def test_cun(backend, name, params):
 
     gate = getattr(gates, name)(0, 1, **params)
 
+    if name == "CRY":
+        decomposition = gate.decompose()
+
     assert gate.unitary
 
     if name != "CU2":
@@ -722,6 +725,12 @@ def test_cun(backend, name, params):
 
     backend.assert_allclose(final_state, target_state, atol=1e-6)
 
+    if name == "CRY":
+        matrix = Circuit(2)
+        matrix.add(decomposition)
+        matrix = matrix.unitary(backend=backend)
+        backend.assert_allclose(matrix, _matrix, atol=1e-10)
+
 
 def test_swap(backend):
     final_state = apply_gates(backend, [gates.X(1), gates.SWAP(0, 1)], nqubits=2)