[stop sequence] support stop sequence (#3025)

* stop seqs in multi-ends

* unittest for gpu stop op

* kernel tid==0

test/operators/test_stop_generation_multi_ends.py

@@ -0,0 +1,58 @@
+# 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.
+
+"""UT for GPU operator stop_generation_multi_ends"""
+
+import numpy as np
+import paddle
+
+from fastdeploy.model_executor.ops.gpu import set_stop_value_multi_ends
+
+
+def test_set_stop_value_multi_ends_with_stop_seq():
+    sampled_token_ids = paddle.to_tensor([[61502], [2]], dtype="int64")
+    stop_flags = paddle.to_tensor([[False], [True]], dtype="bool")
+    seq_lens_this_time = paddle.to_tensor([[1], [0]], dtype="int32")
+    eos_token_id = paddle.to_tensor([2], dtype="int64")
+    next_tokens = paddle.to_tensor([[61502], [2]], dtype="int64")
+
+    pre_ids = paddle.full([2, 32768], -1, dtype="int64")
+    pre_ids[0, :10] = np.array([21, 22, 23, 24, 25, 26, 27, 28, 8038, 61502])
+    step_idx = paddle.to_tensor([[10], [0]], dtype="int64")
+
+    stop_token_ids = paddle.full([2, 5, 8], -1, dtype="int64")
+    stop_token_ids[0, 0, :2] = np.array([8038, 61502])
+
+    stop_seqs_len = paddle.full([2, 5], 10, dtype="int32")
+    stop_seqs_len[0, 0] = 2
+
+    set_stop_value_multi_ends(
+        sampled_token_ids,
+        stop_flags,
+        seq_lens_this_time,
+        eos_token_id,
+        next_tokens,
+        pre_ids,
+        step_idx,
+        stop_token_ids,
+        stop_seqs_len,
+        False,
+    )
+
+    assert stop_flags[0, 0] is True
+    assert sampled_token_ids[0, 0] == 2  # eos token id
+
+
+if __name__ == "__main__":
+    test_set_stop_value_multi_ends_with_stop_seq()