[API compatibility] add scatter_add_ api

python/paddle/__init__.py

@@ -369,6 +369,7 @@
     scatter,
     scatter_,
     scatter_add,
+    scatter_add_,
     scatter_nd,
     scatter_nd_add,
     scatter_reduce,
@@ -1272,6 +1273,7 @@ def __dir__(self):
     'multigammaln_',
     'nan_to_num',
     'nan_to_num_',
+    'scatter_add_',
     'heaviside',
     'tril_indices',
     'index_add',

python/paddle/tensor/__init__.py

@@ -206,6 +206,7 @@
     scatter,
     scatter_,
     scatter_add,
+    scatter_add_,
     scatter_nd,
     scatter_nd_add,
     scatter_reduce,
@@ -830,6 +831,7 @@
     'bernoulli_',
     'exponential_',
     'heaviside',
+    'scatter_add_',
     'index_add',
     "index_add_",
     'index_put',

python/paddle/tensor/manipulation.py

@@ -7319,6 +7319,22 @@ def put_along_axis_(
     )
 
 
+def scatter_add_(
+    input: Tensor,
+    dim: int,
+    index: Tensor,
+    src: Tensor,
+) -> Tensor:
+    """
+    Inplace version of ``scatter_add`` API, the output Tensor will be inplaced with input ``input``.
+    Please refer to :ref:`api_paddle_scatter_add`.
+    """
+
+    return put_along_axis_(
+        input, index, src, dim, 'add', include_self=True, broadcast=False
+    )
+
+
 def index_add(
     x: Tensor, index: Tensor, axis: int, value: Tensor, name: str | None = None
 ) -> Tensor:

test/legacy_test/test_scatter_add_inplace_op.py

@@ -0,0 +1,184 @@
+# 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 copy
+import unittest
+
+import numpy as np
+from op_test import get_places
+
+import paddle
+from paddle.framework import core
+
+
+class TestScatterAddInplaceAPI(unittest.TestCase):
+    def setUp(self):
+        np.random.seed(0)
+        self.shape = [10, 10]
+        self.index_shape = [10, 10]
+        self.index_np = np.random.randint(0, 10, (10, 10)).astype('int64')
+        self.x_np = np.random.random(self.shape).astype(np.float32)
+        self.place = get_places()
+        self.axis = 0
+        self.value_np = np.random.randint(0, 10, (10, 10)).astype(np.float32)
+        self.value_shape = [10, 10]
+
+    def test_inplace_dygraph(self):
+        def run(place):
+            paddle.disable_static(place)
+            x_tensor = paddle.to_tensor(self.x_np)
+            index_tensor = paddle.to_tensor(self.index_np)
+            value_tensor = paddle.to_tensor(self.value_np)
+
+            x_tensor.scatter_add_(self.axis, index_tensor, value_tensor)
+
+            out_ref = copy.deepcopy(self.x_np)
+            for i in range(10):
+                for j in range(10):
+                    out_ref[self.index_np[i, j], j] += self.value_np[i, j]
+
+            np.testing.assert_allclose(x_tensor.numpy(), out_ref, rtol=0.001)
+
+            paddle.enable_static()
+
+        for place in self.place:
+            run(place)
+
+
+@unittest.skipIf(
+    not core.is_compiled_with_cuda(),
+    "core is not compiled with CUDA",
+)
+class TestScatterAddInplaceAPILargeCase(unittest.TestCase):
+    def setUp(self):
+        np.random.seed(0)
+        self.shape = [64, 102400]
+        self.index_shape = [64, 102400]
+        self.index_np = np.random.randint(0, 64, (64, 102400)).astype('int64')
+        self.x_np = np.random.random(self.shape).astype(np.float32)
+        self.axis = 1
+        self.value_np = np.random.randint(0, 50, (64, 102400)).astype(
+            np.float32
+        )
+        self.place = [paddle.CUDAPlace(0)]
+
+    def test_inplace_dygraph(self):
+        def run(place):
+            paddle.disable_static(place)
+            x_tensor = paddle.to_tensor(self.x_np)
+            index_tensor = paddle.to_tensor(self.index_np)
+            value_tensor = paddle.to_tensor(self.value_np)
+
+            x_tensor.scatter_add_(self.axis, index_tensor, value_tensor)
+
+            out_ref = copy.deepcopy(self.x_np)
+            for i in range(64):
+                for j in range(102400):
+                    out_ref[i, self.index_np[i, j]] += self.value_np[i, j]
+
+            np.testing.assert_allclose(x_tensor.numpy(), out_ref, rtol=0.001)
+
+            paddle.enable_static()
+
+        for place in self.place:
+            run(place)
+
+
+class TestScatterAddInplaceAPIOtherCase(unittest.TestCase):
+    def setUp(self):
+        np.random.seed(0)
+        self.shape = [3, 5]
+        self.index1_shape = [1, 4]
+        self.index_np1 = np.array([[0, 1, 2, 0]]).astype('int64')
+        self.index2_shape = [2, 3]
+        self.index_np2 = np.array([[0, 1, 2], [0, 1, 4]]).astype('int64')
+        self.x_np = np.zeros((3, 5)).astype(np.float32)
+        self.value_shape = [2, 5]
+        self.value = (
+            np.arange(1, 11).reshape(self.value_shape).astype(np.float32)
+        )
+        self.place = get_places()
+
+    def test_api_dygraph(self):
+        def run_inplace(place):
+            paddle.disable_static(place)
+            out1 = paddle.to_tensor(self.x_np)
+            index_tensor1 = paddle.to_tensor(self.index_np1)
+            value_tensor = paddle.to_tensor(self.value)
+            out1.scatter_add_(0, index_tensor1, value_tensor)
+            out_ref = copy.deepcopy(self.x_np)
+            for i in range(self.index1_shape[0]):
+                for j in range(self.index1_shape[1]):
+                    out_ref[self.index_np1[i, j], j] += self.value[i, j]
+            np.testing.assert_allclose(out1.numpy(), out_ref, rtol=0.001)
+
+            index_tensor2 = paddle.to_tensor(self.index_np2)
+            out2 = paddle.to_tensor(self.x_np)
+            out2.scatter_add_(1, index_tensor2, value_tensor)
+            out_ref = copy.deepcopy(self.x_np)
+            for i in range(self.index2_shape[0]):
+                for j in range(self.index2_shape[1]):
+                    out_ref[i, self.index_np2[i, j]] += self.value[i, j]
+            np.testing.assert_allclose(out2.numpy(), out_ref, rtol=0.001)
+
+            paddle.enable_static()
+
+        for place in self.place:
+            run_inplace(place)
+
+    def test_error(self):
+        tensorx = paddle.to_tensor([[1, 2, 3], [4, 5, 6]]).astype("float32")
+        indices = paddle.to_tensor([[1, 0, 1], [0, 1, 1]]).astype("int32")
+        values = paddle.to_tensor([1])
+
+        try:
+            tensorx.scatter_add_(0, indices, values)
+        except Exception as error:
+            self.assertIsInstance(error, ValueError)
+
+        indices = paddle.to_tensor([1]).astype("int32")
+        values = paddle.to_tensor([[1, 2, 3], [4, 5, 6]])
+
+        try:
+            tensorx.scatter_add_(0, indices, values)
+        except Exception as error:
+            self.assertIsInstance(error, ValueError)
+
+        indices = paddle.to_tensor(
+            [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
+        ).astype("int32")
+        # indices too large
+        try:
+            tensorx.scatter_add_(0, indices, values)
+        except Exception as error:
+            self.assertIsInstance(error, RuntimeError)
+
+        indices = paddle.to_tensor([[3, 0, 4], [0, 5, 10]]).astype("int32")
+        # the element of indices out of range
+        try:
+            tensorx.scatter_add_(0, indices, values)
+        except Exception as error:
+            self.assertIsInstance(error, RuntimeError)
+
+    def test_index_type_error(self):
+        tensorx = paddle.to_tensor([[1, 2, 3], [4, 5, 6]]).astype("float32")
+        indices = paddle.to_tensor([[1, 0, 1], [0, 1, 1]]).astype("float32")
+        values = paddle.to_tensor([[1, 2, 3], [4, 5, 6]])
+        with self.assertRaises(TypeError):
+            tensorx.scatter_add_(0, indices, values)
+
+
+if __name__ == "__main__":
+    paddle.enable_static()
+    unittest.main()