From 18d59d7620b1172b1ca10c8ab0192f2ca7c5db7c Mon Sep 17 00:00:00 2001
From: Renato Mello <renato.msf@gmail.com>
Date: Fri, 15 Mar 2024 10:49:35 +0400
Subject: [PATCH] move function from `quantum_info.random_ensembles` to
 `backends.__init__`

---
 src/qibo/backends/__init__.py | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/qibo/backends/__init__.py b/src/qibo/backends/__init__.py
index a80c9932e1..0927c3ad97 100644
--- a/src/qibo/backends/__init__.py
+++ b/src/qibo/backends/__init__.py
@@ -1,6 +1,7 @@
 import os
 
-from qibo.backends.abstract import Backend
+import numpy as np
+
 from qibo.backends.clifford import CliffordBackend
 from qibo.backends.npmatrices import NumpyMatrices
 from qibo.backends.numpy import NumpyBackend
@@ -200,3 +201,28 @@ def _check_backend(backend):
         return GlobalBackend()
 
     return backend
+
+def _check_backend_and_local_state(seed, backend):
+    if (
+        seed is not None
+        and not isinstance(seed, int)
+        and not isinstance(seed, np.random.Generator)
+    ):
+        raise_error(
+            TypeError, "seed must be either type int or numpy.random.Generator."
+        )
+
+    backend = _check_backend(backend)
+
+    if seed is None or isinstance(seed, int):
+        if backend.__class__.__name__ in [
+            "CupyBackend",
+            "CuQuantumBackend",
+        ]:  # pragma: no cover
+            local_state = backend.np.random.default_rng(seed)
+        else:
+            local_state = np.random.default_rng(seed)
+    else:
+        local_state = seed
+
+    return backend, local_state