From 834ee27dfc99cc7394e19a0c7c5d8a60c4d4bf5b Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Mon, 22 Apr 2024 11:46:58 -0700
Subject: [PATCH 01/10] Add support for np.random.Generator

---
 cirq-core/cirq/__init__.py           |  1 +
 cirq-core/cirq/value/__init__.py     |  3 ++
 cirq-core/cirq/value/prng.py         | 80 ++++++++++++++++++++++++++++
 cirq-core/cirq/value/prng_test.py    | 48 +++++++++++++++++
 cirq-core/cirq/value/random_state.py |  2 +
 5 files changed, 134 insertions(+)
 create mode 100644 cirq-core/cirq/value/prng.py
 create mode 100644 cirq-core/cirq/value/prng_test.py

diff --git a/cirq-core/cirq/__init__.py b/cirq-core/cirq/__init__.py
index 2dc2034600a..97ac368cafd 100644
--- a/cirq-core/cirq/__init__.py
+++ b/cirq-core/cirq/__init__.py
@@ -536,6 +536,7 @@
     MeasurementKey,
     MeasurementType,
     PeriodicValue,
+    PRNG_OR_SEED_LIKE,
     RANDOM_STATE_OR_SEED_LIKE,
     state_vector_to_probabilities,
     SympyCondition,
diff --git a/cirq-core/cirq/value/__init__.py b/cirq-core/cirq/value/__init__.py
index a810bf108e9..81b39d5bcd0 100644
--- a/cirq-core/cirq/value/__init__.py
+++ b/cirq-core/cirq/value/__init__.py
@@ -65,3 +65,6 @@
 from cirq.value.type_alias import TParamKey, TParamVal, TParamValComplex
 
 from cirq.value.value_equality_attr import value_equality
+
+
+from cirq.value.prng import parse_prng, CustomPRNG, PRNG_OR_SEED_LIKE
diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
new file mode 100644
index 00000000000..237f8717f02
--- /dev/null
+++ b/cirq-core/cirq/value/prng.py
@@ -0,0 +1,80 @@
+# Copyright 2024 The Cirq Developers
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import abc
+from typing import TypeVar, Union, overload
+
+import numpy as np
+
+from cirq._doc import document
+
+
+class CustomPRNG(abc.ABC): ...
+
+
+_CUSTOM_PRNG_T = TypeVar("_CUSTOM_PRNG_T", bound=CustomPRNG)
+_PRNG_T = Union[np.random.Generator, np.random.RandomState, _CUSTOM_PRNG_T]
+_SEED_T = Union[int, None]
+PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator, _CUSTOM_PRNG_T]
+
+document(
+    PRNG_OR_SEED_LIKE,
+    """A pseudorandom number generator or object that can be converted to one.
+
+    If an integer or None, turns into a `np.random.Generator` seeded with that
+    value.
+
+    If none of the above, it is used unmodified. In this case, it is assumed
+    that the object implements whatever methods are required for the use case
+    at hand. For example, it might be an existing instance of `np.random.Generator`
+    or `np.random.RandomState` or a custom pseudorandom number generator implementation
+    and in that case, it has to inherit `cirq.value.CustomPRNG`.
+    """,
+)
+
+
+@overload
+def parse_prng(prng_or_seed: _SEED_T) -> np.random.Generator: ...
+
+
+@overload
+def parse_prng(prng_or_seed: np.random.Generator) -> np.random.Generator: ...
+
+
+@overload
+def parse_prng(prng_or_seed: np.random.RandomState) -> np.random.RandomState: ...
+
+
+@overload
+def parse_prng(prng_or_seed: _CUSTOM_PRNG_T) -> _CUSTOM_PRNG_T: ...
+
+
+def parse_prng(
+    prng_or_seed: PRNG_OR_SEED_LIKE,
+) -> Union[np.random.Generator, np.random.RandomState, _CUSTOM_PRNG_T]:
+    """Interpret an object as a pseudorandom number generator.
+
+    If `prng_or_seed` is None or an integer, returns `np.random.default_rng(prng_or_seed)`.
+    Otherwise, returns `prng_or_seed` unmodified.
+
+    Args:
+        prng_or_seed: The object to be used as or converted to a pseudorandom
+            number generator.
+
+    Returns:
+        The pseudorandom number generator object.
+    """
+    if prng_or_seed is None or isinstance(prng_or_seed, int):
+        return np.random.default_rng(prng_or_seed)
+    return prng_or_seed
diff --git a/cirq-core/cirq/value/prng_test.py b/cirq-core/cirq/value/prng_test.py
new file mode 100644
index 00000000000..741ef012752
--- /dev/null
+++ b/cirq-core/cirq/value/prng_test.py
@@ -0,0 +1,48 @@
+# Copyright 2024 The Cirq Developers
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import List, Union
+import numpy as np
+import cirq
+
+
+class TestPrng(cirq.value.CustomPRNG):
+
+    def random(self, size):
+        return tuple(range(size))
+
+
+def _sample(prng):
+    return tuple(prng.random(10))
+
+
+def test_parse_rng() -> None:
+    eq = cirq.testing.EqualsTester()
+
+    # An `np.random.Generator` or a seed.
+    group_inputs: List[Union[int, np.random.Generator]] = [42, np.random.default_rng(42)]
+    group: List[np.random.Generator] = [cirq.value.parse_prng(s) for s in group_inputs]
+    eq.add_equality_group(*[_sample(g) for g in group])
+
+    # A None seed.
+    prng: np.random.Generator = cirq.value.parse_prng(None)
+    eq.add_equality_group(_sample(prng))
+
+    # Custom PRNG.
+    custom_prng: TestPrng = cirq.value.parse_prng(TestPrng())
+    eq.add_equality_group(_sample(custom_prng))
+
+    # RandomState PRNG.
+    random_state: np.random.RandomState = np.random.RandomState(42)
+    eq.add_equality_group(_sample(cirq.value.parse_prng(random_state)))
diff --git a/cirq-core/cirq/value/random_state.py b/cirq-core/cirq/value/random_state.py
index ab884bd4705..38522a9574a 100644
--- a/cirq-core/cirq/value/random_state.py
+++ b/cirq-core/cirq/value/random_state.py
@@ -33,6 +33,8 @@
     at hand. For example, it might be an existing instance of
     `np.random.RandomState` or a custom pseudorandom number generator
     implementation.
+
+    Note: prefer to use cirq.PRNG_OR_SEED_LIKE.
     """,
 )
 

From 9ce26d6ce5f9d5a39d8d9d816ae181b76d6c0eb2 Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Mon, 22 Apr 2024 12:00:20 -0700
Subject: [PATCH 02/10] serialization

---
 cirq-core/cirq/protocols/json_test_data/spec.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cirq-core/cirq/protocols/json_test_data/spec.py b/cirq-core/cirq/protocols/json_test_data/spec.py
index 22ae86051e0..3a127812fc2 100644
--- a/cirq-core/cirq/protocols/json_test_data/spec.py
+++ b/cirq-core/cirq/protocols/json_test_data/spec.py
@@ -154,6 +154,7 @@
         'QUANTUM_STATE_LIKE',
         'QubitOrderOrList',
         'RANDOM_STATE_OR_SEED_LIKE',
+        'PRNG_OR_SEED_LIKE',
         'STATE_VECTOR_LIKE',
         'Sweepable',
         'TParamKey',

From 30a73e7034846a420bb47b319ee8e1c2d8b3e601 Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Tue, 23 Apr 2024 13:47:59 -0700
Subject: [PATCH 03/10] nit

---
 cirq-core/cirq/value/prng_test.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cirq-core/cirq/value/prng_test.py b/cirq-core/cirq/value/prng_test.py
index 741ef012752..74afdc50150 100644
--- a/cirq-core/cirq/value/prng_test.py
+++ b/cirq-core/cirq/value/prng_test.py
@@ -44,5 +44,5 @@ def test_parse_rng() -> None:
     eq.add_equality_group(_sample(custom_prng))
 
     # RandomState PRNG.
-    random_state: np.random.RandomState = np.random.RandomState(42)
-    eq.add_equality_group(_sample(cirq.value.parse_prng(random_state)))
+    random_state: np.random.RandomState = cirq.value.parse_prng(np.random.RandomState(42))
+    eq.add_equality_group(_sample(random_state))

From c6cfb378853407cf919ba91eb2cdcbdd1a1fd694 Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Wed, 8 May 2024 11:43:47 -0700
Subject: [PATCH 04/10] address comments

---
 cirq-core/cirq/value/__init__.py          |  2 +-
 cirq-core/cirq/value/prng.py              | 65 +++++++++--------------
 cirq-core/cirq/value/prng_test.py         | 26 ++++-----
 cirq-core/cirq/value/random_state.py      | 10 +++-
 cirq-core/cirq/value/random_state_test.py |  2 +
 5 files changed, 50 insertions(+), 55 deletions(-)

diff --git a/cirq-core/cirq/value/__init__.py b/cirq-core/cirq/value/__init__.py
index 81b39d5bcd0..4847b1ff5a5 100644
--- a/cirq-core/cirq/value/__init__.py
+++ b/cirq-core/cirq/value/__init__.py
@@ -67,4 +67,4 @@
 from cirq.value.value_equality_attr import value_equality
 
 
-from cirq.value.prng import parse_prng, CustomPRNG, PRNG_OR_SEED_LIKE
+from cirq.value.prng import parse_prng, PRNG_OR_SEED_LIKE
diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index 237f8717f02..1dbd2d49f8d 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -12,61 +12,38 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import abc
-from typing import TypeVar, Union, overload
+from typing import Union
 
+import numbers
 import numpy as np
 
 from cirq._doc import document
+from cirq.value.random_state import RANDOM_STATE_OR_SEED_LIKE
 
-
-class CustomPRNG(abc.ABC): ...
-
-
-_CUSTOM_PRNG_T = TypeVar("_CUSTOM_PRNG_T", bound=CustomPRNG)
-_PRNG_T = Union[np.random.Generator, np.random.RandomState, _CUSTOM_PRNG_T]
 _SEED_T = Union[int, None]
-PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator, _CUSTOM_PRNG_T]
+PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator]
 
 document(
     PRNG_OR_SEED_LIKE,
     """A pseudorandom number generator or object that can be converted to one.
 
-    If an integer or None, turns into a `np.random.Generator` seeded with that
-    value.
-
-    If none of the above, it is used unmodified. In this case, it is assumed
-    that the object implements whatever methods are required for the use case
-    at hand. For example, it might be an existing instance of `np.random.Generator`
-    or `np.random.RandomState` or a custom pseudorandom number generator implementation
-    and in that case, it has to inherit `cirq.value.CustomPRNG`.
+    If is an integer or None, turns into a `np.random.Generator` seeded with that value.
+    If is an instance of `np.random.Generator` or a subclass of it, return as is.
+    If is an instance of `np.random.RandomState` or has a `randint` method, returns
+    `np.random.default_rng(rs.randint(2**63 - 1))`
     """,
 )
 
 
-@overload
-def parse_prng(prng_or_seed: _SEED_T) -> np.random.Generator: ...
-
-
-@overload
-def parse_prng(prng_or_seed: np.random.Generator) -> np.random.Generator: ...
-
-
-@overload
-def parse_prng(prng_or_seed: np.random.RandomState) -> np.random.RandomState: ...
-
-
-@overload
-def parse_prng(prng_or_seed: _CUSTOM_PRNG_T) -> _CUSTOM_PRNG_T: ...
-
-
 def parse_prng(
-    prng_or_seed: PRNG_OR_SEED_LIKE,
-) -> Union[np.random.Generator, np.random.RandomState, _CUSTOM_PRNG_T]:
+    prng_or_seed: Union[PRNG_OR_SEED_LIKE, RANDOM_STATE_OR_SEED_LIKE]
+) -> np.random.Generator:
     """Interpret an object as a pseudorandom number generator.
 
+    If `prng_or_seed` is an `np.random.Generator`, return it unmodified.
     If `prng_or_seed` is None or an integer, returns `np.random.default_rng(prng_or_seed)`.
-    Otherwise, returns `prng_or_seed` unmodified.
+    If `prng_or_seed` is an instance of `np.random.RandomState` or has a `randint` method,
+        returns `np.random.default_rng(prng_or_seed.randint(2**63 - 1))`.
 
     Args:
         prng_or_seed: The object to be used as or converted to a pseudorandom
@@ -74,7 +51,17 @@ def parse_prng(
 
     Returns:
         The pseudorandom number generator object.
+
+    Raises:
+        TypeError: If `prng_or_seed` is can't be converted to an np.random.Generator.
     """
-    if prng_or_seed is None or isinstance(prng_or_seed, int):
-        return np.random.default_rng(prng_or_seed)
-    return prng_or_seed
+    if isinstance(prng_or_seed, np.random.Generator):
+        return prng_or_seed
+    if prng_or_seed is None or isinstance(prng_or_seed, numbers.Integral):
+        return np.random.default_rng(prng_or_seed if prng_or_seed is None else int(prng_or_seed))
+    if isinstance(prng_or_seed, np.random.RandomState):
+        return np.random.default_rng(prng_or_seed.randint(2**63 - 1))
+    randint = getattr(prng_or_seed, "randint", None)
+    if randint is not None:
+        return np.random.default_rng(randint(2**63 - 1))
+    raise TypeError(f"{prng_or_seed} can't be converted to a pseudorandom number generator")
diff --git a/cirq-core/cirq/value/prng_test.py b/cirq-core/cirq/value/prng_test.py
index 74afdc50150..9ca84ae46bf 100644
--- a/cirq-core/cirq/value/prng_test.py
+++ b/cirq-core/cirq/value/prng_test.py
@@ -13,14 +13,11 @@
 # limitations under the License.
 
 from typing import List, Union
-import numpy as np
-import cirq
-
 
-class TestPrng(cirq.value.CustomPRNG):
+import pytest
+import numpy as np
 
-    def random(self, size):
-        return tuple(range(size))
+import cirq
 
 
 def _sample(prng):
@@ -36,13 +33,16 @@ def test_parse_rng() -> None:
     eq.add_equality_group(*[_sample(g) for g in group])
 
     # A None seed.
-    prng: np.random.Generator = cirq.value.parse_prng(None)
+    prng = cirq.value.parse_prng(None)
     eq.add_equality_group(_sample(prng))
 
-    # Custom PRNG.
-    custom_prng: TestPrng = cirq.value.parse_prng(TestPrng())
-    eq.add_equality_group(_sample(custom_prng))
-
     # RandomState PRNG.
-    random_state: np.random.RandomState = cirq.value.parse_prng(np.random.RandomState(42))
-    eq.add_equality_group(_sample(random_state))
+    prng = cirq.value.parse_prng(np.random.RandomState(42))
+    eq.add_equality_group(_sample(prng))
+
+    # np.random module
+    prng = cirq.value.parse_prng(np.random)
+    eq.add_equality_group(_sample(prng))
+
+    with pytest.raises(TypeError):
+        _ = cirq.value.parse_prng(1.0)
diff --git a/cirq-core/cirq/value/random_state.py b/cirq-core/cirq/value/random_state.py
index 38522a9574a..771b80634f0 100644
--- a/cirq-core/cirq/value/random_state.py
+++ b/cirq-core/cirq/value/random_state.py
@@ -28,6 +28,9 @@
     If an integer, turns into a `np.random.RandomState` seeded with that
     integer.
 
+    If `random_state` is an instance of `np.random.Generator`, returns a
+        `np.random.RandomState` seeded with `random_state.bit_generator`.
+
     If none of the above, it is used unmodified. In this case, it is assumed
     that the object implements whatever methods are required for the use case
     at hand. For example, it might be an existing instance of
@@ -43,8 +46,9 @@ def parse_random_state(random_state: RANDOM_STATE_OR_SEED_LIKE) -> np.random.Ran
     """Interpret an object as a pseudorandom number generator.
 
     If `random_state` is None, returns the module `np.random`.
-    If `random_state` is an integer, returns
-    `np.random.RandomState(random_state)`.
+    If `random_state` is an integer, returns `np.random.RandomState(random_state)`.
+    If `random_state` is an instance of `np.random.Generator`, returns a
+        `np.random.RandomState` seeded with `random_state.bit_generator`.
     Otherwise, returns `random_state` unmodified.
 
     Args:
@@ -58,5 +62,7 @@ def parse_random_state(random_state: RANDOM_STATE_OR_SEED_LIKE) -> np.random.Ran
         return cast(np.random.RandomState, np.random)
     elif isinstance(random_state, int):
         return np.random.RandomState(random_state)
+    elif isinstance(random_state, np.random.Generator):
+        return np.random.RandomState(random_state.bit_generator)
     else:
         return cast(np.random.RandomState, random_state)
diff --git a/cirq-core/cirq/value/random_state_test.py b/cirq-core/cirq/value/random_state_test.py
index 694965ea0a9..3f74ea0932e 100644
--- a/cirq-core/cirq/value/random_state_test.py
+++ b/cirq-core/cirq/value/random_state_test.py
@@ -42,3 +42,5 @@ def rand(prng):
     vals = [prng.rand() for prng in prngs]
     eq = cirq.testing.EqualsTester()
     eq.add_equality_group(*vals)
+
+    eq.add_equality_group(cirq.value.parse_random_state(np.random.default_rng(0)).rand())

From d5ade4f4365a571b18b2d9ebfbe01d2e490ab2e8 Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Wed, 8 May 2024 11:47:22 -0700
Subject: [PATCH 05/10] nit

---
 cirq-core/cirq/value/prng.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index 1dbd2d49f8d..8bdfa731a7b 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -20,7 +20,6 @@
 from cirq._doc import document
 from cirq.value.random_state import RANDOM_STATE_OR_SEED_LIKE
 
-_SEED_T = Union[int, None]
 PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator]
 
 document(

From 1e9c7ab362ebdf7135ca93571f5a6c7428840ed3 Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Wed, 8 May 2024 12:02:12 -0700
Subject: [PATCH 06/10] nit

---
 cirq-core/cirq/value/prng.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index 8bdfa731a7b..ea7492413bd 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -29,7 +29,7 @@
     If is an integer or None, turns into a `np.random.Generator` seeded with that value.
     If is an instance of `np.random.Generator` or a subclass of it, return as is.
     If is an instance of `np.random.RandomState` or has a `randint` method, returns
-    `np.random.default_rng(rs.randint(2**63 - 1))`
+    `np.random.default_rng(rs.randint(2**31 - 1))`
     """,
 )
 
@@ -42,7 +42,7 @@ def parse_prng(
     If `prng_or_seed` is an `np.random.Generator`, return it unmodified.
     If `prng_or_seed` is None or an integer, returns `np.random.default_rng(prng_or_seed)`.
     If `prng_or_seed` is an instance of `np.random.RandomState` or has a `randint` method,
-        returns `np.random.default_rng(prng_or_seed.randint(2**63 - 1))`.
+        returns `np.random.default_rng(prng_or_seed.randint(2**31 - 1))`.
 
     Args:
         prng_or_seed: The object to be used as or converted to a pseudorandom
@@ -59,8 +59,8 @@ def parse_prng(
     if prng_or_seed is None or isinstance(prng_or_seed, numbers.Integral):
         return np.random.default_rng(prng_or_seed if prng_or_seed is None else int(prng_or_seed))
     if isinstance(prng_or_seed, np.random.RandomState):
-        return np.random.default_rng(prng_or_seed.randint(2**63 - 1))
+        return np.random.default_rng(prng_or_seed.randint(2**31 - 1))
     randint = getattr(prng_or_seed, "randint", None)
     if randint is not None:
-        return np.random.default_rng(randint(2**63 - 1))
+        return np.random.default_rng(randint(2**31 - 1))
     raise TypeError(f"{prng_or_seed} can't be converted to a pseudorandom number generator")

From aff9556bb437a7855819b5ca0993d5cf69b51f56 Mon Sep 17 00:00:00 2001
From: Nour Yosri <noureldinyosri@gmail.com>
Date: Wed, 8 May 2024 12:02:47 -0700
Subject: [PATCH 07/10] nit

---
 cirq-core/cirq/value/prng.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index ea7492413bd..86440ccee3d 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -29,7 +29,7 @@
     If is an integer or None, turns into a `np.random.Generator` seeded with that value.
     If is an instance of `np.random.Generator` or a subclass of it, return as is.
     If is an instance of `np.random.RandomState` or has a `randint` method, returns
-    `np.random.default_rng(rs.randint(2**31 - 1))`
+    `np.random.default_rng(rs.randint(2**31))`
     """,
 )
 
@@ -42,7 +42,7 @@ def parse_prng(
     If `prng_or_seed` is an `np.random.Generator`, return it unmodified.
     If `prng_or_seed` is None or an integer, returns `np.random.default_rng(prng_or_seed)`.
     If `prng_or_seed` is an instance of `np.random.RandomState` or has a `randint` method,
-        returns `np.random.default_rng(prng_or_seed.randint(2**31 - 1))`.
+        returns `np.random.default_rng(prng_or_seed.randint(2**31))`.
 
     Args:
         prng_or_seed: The object to be used as or converted to a pseudorandom
@@ -59,8 +59,8 @@ def parse_prng(
     if prng_or_seed is None or isinstance(prng_or_seed, numbers.Integral):
         return np.random.default_rng(prng_or_seed if prng_or_seed is None else int(prng_or_seed))
     if isinstance(prng_or_seed, np.random.RandomState):
-        return np.random.default_rng(prng_or_seed.randint(2**31 - 1))
+        return np.random.default_rng(prng_or_seed.randint(2**31))
     randint = getattr(prng_or_seed, "randint", None)
     if randint is not None:
-        return np.random.default_rng(randint(2**31 - 1))
+        return np.random.default_rng(randint(2**31))
     raise TypeError(f"{prng_or_seed} can't be converted to a pseudorandom number generator")

From b5431f28cbf4ee3594d25e5b265e7d04efd4888f Mon Sep 17 00:00:00 2001
From: Revanth Gundala <revanth.gundala@gmail.com>
Date: Tue, 22 Apr 2025 16:11:24 -0700
Subject: [PATCH 08/10] Updated PR based on comments

---
 cirq-core/cirq/value/prng.py      | 76 +++++++++++++++++++-----------
 cirq-core/cirq/value/prng_test.py | 77 ++++++++++++++++++++++---------
 2 files changed, 105 insertions(+), 48 deletions(-)

diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index 86440ccee3d..5b1f43b7d04 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -12,55 +12,77 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Union
-
 import numbers
 import numpy as np
+from typing import Union
 
 from cirq._doc import document
-from cirq.value.random_state import RANDOM_STATE_OR_SEED_LIKE
 
-PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator]
 
+PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator]
 document(
     PRNG_OR_SEED_LIKE,
     """A pseudorandom number generator or object that can be converted to one.
 
-    If is an integer or None, turns into a `np.random.Generator` seeded with that value.
-    If is an instance of `np.random.Generator` or a subclass of it, return as is.
-    If is an instance of `np.random.RandomState` or has a `randint` method, returns
-    `np.random.default_rng(rs.randint(2**31))`
+    Can be an instance of `np.random.Generator`, `np.random.RandomState`,
+    an integer seed, or None.
     """,
 )
 
+# Singleton generator instance for None input, created on demand.
+# Avoids creating many Generators if parse_prng(None) is called frequently.
+_NONE_PRNG_INSTANCE: np.random.Generator = None
+
+def _get_none_prng_instance() -> np.random.Generator:
+    """Returns the singleton PRNG instance used for None inputs."""
+    global _NONE_PRNG_INSTANCE
+    if _NONE_PRNG_INSTANCE is None:
+        _NONE_PRNG_INSTANCE = np.random.default_rng(None)
+    return _NONE_PRNG_INSTANCE
 
-def parse_prng(
-    prng_or_seed: Union[PRNG_OR_SEED_LIKE, RANDOM_STATE_OR_SEED_LIKE]
-) -> np.random.Generator:
-    """Interpret an object as a pseudorandom number generator.
+def parse_prng(prng_or_seed: PRNG_OR_SEED_LIKE) -> np.random.Generator:
+    """Converts the input object into a `numpy.random.Generator`.
 
-    If `prng_or_seed` is an `np.random.Generator`, return it unmodified.
-    If `prng_or_seed` is None or an integer, returns `np.random.default_rng(prng_or_seed)`.
-    If `prng_or_seed` is an instance of `np.random.RandomState` or has a `randint` method,
-        returns `np.random.default_rng(prng_or_seed.randint(2**31))`.
+    - If `prng_or_seed` is already a `np.random.Generator`, it's returned directly.
+    - If `prng_or_seed` is `None`, returns a singleton `np.random.Generator`
+      instance (seeded unpredictably by NumPy).
+    - If `prng_or_seed` is an integer, returns `np.random.default_rng(prng_or_seed)`.
+    - If `prng_or_seed` is an instance of `np.random.RandomState`, returns a `np.random.Generator` initialized with the RandomState's bit generator or falls back on a random seed.
+    - Passing the `np.random` module itself is explicitly disallowed.
 
     Args:
-        prng_or_seed: The object to be used as or converted to a pseudorandom
-            number generator.
+        prng_or_seed: The object to be used as or converted to a Generator.
 
     Returns:
-        The pseudorandom number generator object.
+        The `numpy.random.Generator` object.
 
     Raises:
-        TypeError: If `prng_or_seed` is can't be converted to an np.random.Generator.
+        TypeError: If `prng_or_seed` is the `np.random` module or cannot be
+            converted to a `np.random.Generator`.
     """
+    if prng_or_seed is np.random:
+        raise TypeError(
+            "Passing the 'np.random' module is not supported. "
+            "Use None to get a default np.random.Generator instance."
+        )
+
     if isinstance(prng_or_seed, np.random.Generator):
         return prng_or_seed
-    if prng_or_seed is None or isinstance(prng_or_seed, numbers.Integral):
-        return np.random.default_rng(prng_or_seed if prng_or_seed is None else int(prng_or_seed))
+
+    if prng_or_seed is None:
+        return _get_none_prng_instance()
+
+    if isinstance(prng_or_seed, numbers.Integral):
+        return np.random.default_rng(int(prng_or_seed))
+
     if isinstance(prng_or_seed, np.random.RandomState):
-        return np.random.default_rng(prng_or_seed.randint(2**31))
-    randint = getattr(prng_or_seed, "randint", None)
-    if randint is not None:
-        return np.random.default_rng(randint(2**31))
-    raise TypeError(f"{prng_or_seed} can't be converted to a pseudorandom number generator")
+        bit_gen = getattr(prng_or_seed, '_bit_generator', None)
+        if bit_gen is not None:
+            return np.random.default_rng(bit_gen)
+        seed_val = prng_or_seed.randint(2**31)
+        return np.random.default_rng(seed_val)
+
+    raise TypeError(
+        f"Input {prng_or_seed} (type: {type(prng_or_seed).__name__}) cannot be converted "
+        f"to a {np.random.Generator.__name__}"
+    )
\ No newline at end of file
diff --git a/cirq-core/cirq/value/prng_test.py b/cirq-core/cirq/value/prng_test.py
index 9ca84ae46bf..f159bcf6f8c 100644
--- a/cirq-core/cirq/value/prng_test.py
+++ b/cirq-core/cirq/value/prng_test.py
@@ -12,37 +12,72 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import List, Union
-
 import pytest
 import numpy as np
 
 import cirq
 
 
-def _sample(prng):
-    return tuple(prng.random(10))
+def test_parse_prng_generator_passthrough():
+    """Test that passing an existing Generator returns the same object."""
+    rng = np.random.default_rng(12345)
+    assert cirq.value.parse_prng(rng) is rng
 
 
-def test_parse_rng() -> None:
-    eq = cirq.testing.EqualsTester()
+def test_parse_prng_none_singleton():
+    """Test that passing None returns a reusable singleton Generator."""
+    rng1 = cirq.value.parse_prng(None)
+    rng2 = cirq.value.parse_prng(None)
+    assert rng1 is rng2
+
+
+def test_parse_prng_int_seeding():
+    """Test that integer seeds create predictable Generators."""
+    rng_int = cirq.value.parse_prng(42)
+    rng_npint = cirq.value.parse_prng(np.int64(42))
+    assert rng_int.random() == rng_npint.random()
+
+    rng_different_seed = cirq.value.parse_prng(43)
+    rng_int = cirq.value.parse_prng(42)
+    assert rng_int.random() != rng_different_seed.random()
+
+
+def test_parse_prng_module_disallowed():
+    """Test that passing the np.random module raises TypeError."""
+    with pytest.raises(TypeError, match="not supported"):
+        cirq.value.parse_prng(np.random)
 
-    # An `np.random.Generator` or a seed.
-    group_inputs: List[Union[int, np.random.Generator]] = [42, np.random.default_rng(42)]
-    group: List[np.random.Generator] = [cirq.value.parse_prng(s) for s in group_inputs]
-    eq.add_equality_group(*[_sample(g) for g in group])
 
-    # A None seed.
-    prng = cirq.value.parse_prng(None)
-    eq.add_equality_group(_sample(prng))
+def test_parse_prng_invalid_types():
+    """Test that unsupported types raise TypeError."""
+
+    match = "cannot be converted"
+    with pytest.raises(TypeError, match=match):
+        cirq.value.parse_prng(1.0)
+
+    with pytest.raises(TypeError, match=match):
+        cirq.value.parse_prng("not a seed")
+
+    with pytest.raises(TypeError, match=match):
+        cirq.value.parse_prng([1, 2, 3])
+
+    with pytest.raises(TypeError, match=match):
+        cirq.value.parse_prng(object())
+
+
+def test_parse_prng_equality_tester_on_output():
+    """Use EqualsTester to verify output consistency for valid inputs."""
+    eq = cirq.testing.EqualsTester()
 
-    # RandomState PRNG.
-    prng = cirq.value.parse_prng(np.random.RandomState(42))
-    eq.add_equality_group(_sample(prng))
+    eq.add_equality_group(
+        cirq.value.parse_prng(42).random(),
+        cirq.value.parse_prng(np.int32(42)).random(),
+        cirq.value.parse_prng(np.random.default_rng(42)).random(),
+    )
 
-    # np.random module
-    prng = cirq.value.parse_prng(np.random)
-    eq.add_equality_group(_sample(prng))
+    eq.add_equality_group(
+        cirq.value.parse_prng(np.random.RandomState(50)).random(),
+        cirq.value.parse_prng(np.random.RandomState(50)).random(),
+    )
 
-    with pytest.raises(TypeError):
-        _ = cirq.value.parse_prng(1.0)
+    eq.add_equality_group(cirq.value.parse_prng(None).random())
\ No newline at end of file

From 5596b2572b52d4fc22064b6ea4cbc902527b8db8 Mon Sep 17 00:00:00 2001
From: Revanth Gundala <revanth.gundala@gmail.com>
Date: Tue, 17 Jun 2025 11:13:07 -0700
Subject: [PATCH 09/10] fix: Remove singleton PRNG pattern and update copyright
 year

---
 cirq-core/cirq/value/prng.py | 21 +++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index 5b1f43b7d04..39f2f99a512 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -1,4 +1,4 @@
-# Copyright 2024 The Cirq Developers
+# Copyright 2025 The Cirq Developers
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -19,32 +19,21 @@
 from cirq._doc import document
 
 
+# Type for PRNG or seed-like input.
 PRNG_OR_SEED_LIKE = Union[None, int, np.random.RandomState, np.random.Generator]
 document(
     PRNG_OR_SEED_LIKE,
     """A pseudorandom number generator or object that can be converted to one.
 
-    Can be an instance of `np.random.Generator`, `np.random.RandomState`,
-    an integer seed, or None.
+    Can be an instance of `np.random.Generator`, an integer seed, a `np.random.RandomState`, or None.
     """,
 )
 
-# Singleton generator instance for None input, created on demand.
-# Avoids creating many Generators if parse_prng(None) is called frequently.
-_NONE_PRNG_INSTANCE: np.random.Generator = None
-
-def _get_none_prng_instance() -> np.random.Generator:
-    """Returns the singleton PRNG instance used for None inputs."""
-    global _NONE_PRNG_INSTANCE
-    if _NONE_PRNG_INSTANCE is None:
-        _NONE_PRNG_INSTANCE = np.random.default_rng(None)
-    return _NONE_PRNG_INSTANCE
-
 def parse_prng(prng_or_seed: PRNG_OR_SEED_LIKE) -> np.random.Generator:
     """Converts the input object into a `numpy.random.Generator`.
 
     - If `prng_or_seed` is already a `np.random.Generator`, it's returned directly.
-    - If `prng_or_seed` is `None`, returns a singleton `np.random.Generator`
+    - If `prng_or_seed` is `None`, returns a new `np.random.Generator`
       instance (seeded unpredictably by NumPy).
     - If `prng_or_seed` is an integer, returns `np.random.default_rng(prng_or_seed)`.
     - If `prng_or_seed` is an instance of `np.random.RandomState`, returns a `np.random.Generator` initialized with the RandomState's bit generator or falls back on a random seed.
@@ -70,7 +59,7 @@ def parse_prng(prng_or_seed: PRNG_OR_SEED_LIKE) -> np.random.Generator:
         return prng_or_seed
 
     if prng_or_seed is None:
-        return _get_none_prng_instance()
+        return np.random.default_rng()
 
     if isinstance(prng_or_seed, numbers.Integral):
         return np.random.default_rng(int(prng_or_seed))

From ef4f34e5292c761e0c60779e9ca60906322b929a Mon Sep 17 00:00:00 2001
From: Revanth Gundala <revanth.gundala@gmail.com>
Date: Tue, 17 Jun 2025 11:46:28 -0700
Subject: [PATCH 10/10] updated format

---
 cirq-core/cirq/value/prng.py      |  3 ++-
 cirq-core/cirq/value/prng_test.py | 10 ++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/cirq-core/cirq/value/prng.py b/cirq-core/cirq/value/prng.py
index 39f2f99a512..ade9f4cb6b0 100644
--- a/cirq-core/cirq/value/prng.py
+++ b/cirq-core/cirq/value/prng.py
@@ -29,6 +29,7 @@
     """,
 )
 
+
 def parse_prng(prng_or_seed: PRNG_OR_SEED_LIKE) -> np.random.Generator:
     """Converts the input object into a `numpy.random.Generator`.
 
@@ -74,4 +75,4 @@ def parse_prng(prng_or_seed: PRNG_OR_SEED_LIKE) -> np.random.Generator:
     raise TypeError(
         f"Input {prng_or_seed} (type: {type(prng_or_seed).__name__}) cannot be converted "
         f"to a {np.random.Generator.__name__}"
-    )
\ No newline at end of file
+    )
diff --git a/cirq-core/cirq/value/prng_test.py b/cirq-core/cirq/value/prng_test.py
index f159bcf6f8c..33d99a1d3b4 100644
--- a/cirq-core/cirq/value/prng_test.py
+++ b/cirq-core/cirq/value/prng_test.py
@@ -24,11 +24,13 @@ def test_parse_prng_generator_passthrough():
     assert cirq.value.parse_prng(rng) is rng
 
 
-def test_parse_prng_none_singleton():
-    """Test that passing None returns a reusable singleton Generator."""
+def test_parse_prng_none():
+    """Test that passing None returns a new Generator instance."""
     rng1 = cirq.value.parse_prng(None)
     rng2 = cirq.value.parse_prng(None)
-    assert rng1 is rng2
+    assert rng1 is not rng2
+    assert type(rng1) is np.random.Generator
+    assert type(rng2) is np.random.Generator
 
 
 def test_parse_prng_int_seeding():
@@ -80,4 +82,4 @@ def test_parse_prng_equality_tester_on_output():
         cirq.value.parse_prng(np.random.RandomState(50)).random(),
     )
 
-    eq.add_equality_group(cirq.value.parse_prng(None).random())
\ No newline at end of file
+    eq.add_equality_group(cirq.value.parse_prng(None).random())