[Fix] Export available engines for qd+ (#262)

pyproject.toml

@@ -19,7 +19,7 @@ authors = [
 ]
 requires-python = ">=3.9,<3.12"
 license = {text = "Apache 2.0"}
-version = "1.2.1"
+version = "1.2.2"
 classifiers=[
     "License :: OSI Approved :: Apache Software License",
     "Programming Language :: Python",

qadence/extensions.py

@@ -113,6 +113,7 @@ def _set_backend_config(backend: Backend, diff_mode: DiffMode) -> None:
 try:
     module = importlib.import_module("qadence_extensions.extensions")
     available_backends = getattr(module, "available_backends")
+    available_engines = getattr(module, "available_engines")
     supported_gates = getattr(module, "supported_gates")
     get_gpsr_fns = getattr(module, "gpsr_fns")
     set_backend_config = getattr(module, "set_backend_config")

qadence/types.py

@@ -202,15 +202,22 @@ class _BackendName(StrEnum):
     """The horqrux backend."""
 
 
+class _Engine(StrEnum):
+    TORCH = "torch"
+    JAX = "jax"
+
+
 # If proprietary qadence_extensions is available, import the
 # right function since more backends are supported.
 try:
     module = importlib.import_module("qadence_extensions.types")
     BackendName = getattr(module, "BackendName")
     DiffMode = getattr(module, "DiffMode")
+    Engine = getattr(module, "Engine")
 except ModuleNotFoundError:
     BackendName = _BackendName
     DiffMode = _DiffMode
+    Engine = _Engine
 
 
 class StateGeneratorType(StrEnum):
@@ -391,10 +398,5 @@ class ReadOutOptimization(StrEnum):
     CONSTRAINED = "constrained"
 
 
-class Engine(StrEnum):
-    TORCH = "torch"
-    JAX = "jax"
-
-
 ParamDictType = dict[str, ArrayLike]
 DifferentiableExpression = Callable[..., ArrayLike]