Merge pull request #1015 from qiboteam/save_gates

Save gates to JSON

src/qibo/gates/abstract.py

@@ -1,11 +1,15 @@
 import collections
+import json
 from typing import List, Sequence, Tuple
 
 import sympy
 
 from qibo.backends import GlobalBackend
 from qibo.config import raise_error
 
+REQUIRED_FIELDS = ["name", "init_kwargs", "_target_qubits", "_control_qubits"]
+REQUIRED_FIELDS_INIT_KWARGS = ["theta", "phi", "lam"]
+
 
 class Gate:
     """The base class for gate implementation.
@@ -50,6 +54,24 @@ def __init__(self):
         self.device_gates = set()
         self.original_gate = None
 
+    def to_json(self):
+        encoded = self.__dict__
+
+        encoded_simple = {
+            key: value for key, value in encoded.items() if key in REQUIRED_FIELDS
+        }
+
+        encoded_simple["init_kwargs"] = {
+            key: value
+            for key, value in encoded_simple["init_kwargs"].items()
+            if key in REQUIRED_FIELDS_INIT_KWARGS
+        }
+
+        for value in encoded_simple:
+            if isinstance(encoded[value], set):
+                encoded_simple[value] = list(encoded_simple[value])
+        return json.dumps(encoded_simple)
+
     @property
     def target_qubits(self) -> Tuple[int]:
         """Tuple with ids of target qubits."""

tests/test_gates_abstract.py

@@ -1,4 +1,6 @@
 """Tests methods defined in `qibo/gates/abstract.py` and `qibo/gates/gates.py`."""
+import json
+
 import numpy as np
 import pytest
 
@@ -14,6 +16,22 @@ def test_one_qubit_gates_init(gatename):
     assert gate.target_qubits == (0,)
 
 
+@pytest.mark.parametrize(
+    "gatename", ["H", "X", "Y", "Z", "S", "SDG", "T", "TDG", "I", "Align"]
+)
+def test_one_qubit_gates_to_json(gatename):
+    gate = getattr(gates, gatename)(0)
+
+    json_general = (
+        '{"name": {}, "init_kwargs": {}, "_target_qubits": [0], "_control_qubits": []}'
+    )
+
+    json_gate = json.loads(json_general)
+    json_gate["name"] = gate.name
+
+    assert gate.to_json() == json.dumps(json_gate)
+
+
 @pytest.mark.parametrize(
     "controls,instance", [((1,), "CNOT"), ((1, 2), "TOFFOLI"), ((1, 2, 4), "X")]
 )
@@ -93,6 +111,32 @@ def test_one_qubit_rotations_init(gatename, params):
     assert gate.parameters == params
 
 
+@pytest.mark.parametrize(
+    "gatename,params",
+    [
+        ("RX", (0.1234,)),
+        ("RY", (0.1234,)),
+        ("RZ", (0.1234,)),
+        ("U1", (0.1234,)),
+        ("U2", (0.1234, 0.4321)),
+        ("U3", (0.1234, 0.4321, 0.5678)),
+    ],
+)
+def test_one_qubit_rotations_to_json(gatename, params):
+    gate = getattr(gates, gatename)(0, *params)
+
+    json_general = (
+        '{"name": {}, "init_kwargs": {}, "_target_qubits": [0], "_control_qubits": []}'
+    )
+
+    json_gate = json.loads(json_general)
+    json_gate["name"] = gate.name
+    json_gate["init_kwargs"] = gate.init_kwargs
+    del json_gate["init_kwargs"]["trainable"]
+
+    assert gate.to_json() == json.dumps(json_gate)
+
+
 @pytest.mark.parametrize(
     "gatename,params",
     [