[API compatibility] add paddle.compat.seed method (PaddlePaddle#76440)

* add paddle.compat.seed method

* add paddle.compat.seed method

* add api doc

* add xpu test

* add xpu test

Author: blacksheep-Aristotle

python/paddle/compat/__init__.py

@@ -18,6 +18,7 @@
 
 import paddle
 from paddle import _C_ops
+from paddle.base import core
 from paddle.base.framework import Variable
 from paddle.framework import (
     in_dynamic_mode,
@@ -47,6 +48,7 @@
     'max',
     'median',
     'nanmedian',
+    'seed',
 ]
 
 
@@ -234,6 +236,22 @@ def nanmedian(
         return MedianRetType(values=values, indices=indices)
 
 
+def seed() -> int:
+    r"""Sets the seed for generating random numbers to a non-deterministic
+    random number on all devices. Returns a 64 bit number used to seed the RNG.
+    Returns:
+        Returns: int64, the seed used to seed the RNG.
+    Examples:
+        .. code-block:: python
+
+            >>> import paddle
+            >>> seed = paddle.compat.seed()
+    """
+    seed = core.default_cpu_generator().seed()
+    paddle.seed(seed)
+    return seed
+
+
 class MinMaxRetType(NamedTuple):
     values: Tensor
     indices: Tensor

test/legacy_test/test_compat_seed.py

@@ -0,0 +1,51 @@
+# Copyright (c) 2025 PaddlePaddle Authors. All Rights Reserved.
+#
+# 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
+#
+#     http://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 unittest
+
+import paddle
+from paddle.base import core
+from paddle.compat import seed as compat_seed
+
+
+class TestCompatSeed(unittest.TestCase):
+    def test_seed(self):
+        paddle.seed(42)
+        seed_cpu_random = core.default_cpu_generator().random()
+        if paddle.is_compiled_with_cuda():
+            seed_gpu_random = core.default_cuda_generator(0).random()
+        if paddle.is_compiled_with_xpu():
+            seed_xpu_random = core.default_xpu_generator(0).random()
+        paddle.seed(42)
+        compat_seed()
+        compat_seed_cpu_random = core.default_cpu_generator().random()
+
+        if paddle.is_compiled_with_cuda():
+            compat_seed_gpu_random = core.default_cuda_generator(0).random()
+            assert seed_gpu_random != compat_seed_gpu_random, (
+                "GPU Random Seed Not Change!"
+            )
+        if paddle.is_compiled_with_xpu():
+            compat_seed_xpu_random = core.default_xpu_generator(0).random()
+            assert seed_xpu_random != compat_seed_xpu_random, (
+                "XPU Random Seed Not Change!"
+            )
+
+        assert seed_cpu_random != compat_seed_cpu_random, (
+            "CPU Random Seed Not Change!"
+        )
+
+
+if __name__ == '__main__':
+    unittest.main()