# Copyright (c) 2022 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 numpy as np

import paddle
from paddle.sparse import nn


class TestGradientAdd(unittest.TestCase):
    def sparse(self, sp_x):
        identity = sp_x
        out = nn.functional.relu(sp_x)
        values = out.values() + identity.values()
        out = paddle.sparse.sparse_coo_tensor(
            out.indices(),
            values,
            shape=out.shape,
            stop_gradient=out.stop_gradient,
        )
        return out

    def dense(self, x):
        identity = x
        out = paddle.nn.functional.relu(x)
        out = out + identity
        return out

    def test(self):
        x = paddle.randn((3, 3))
        sparse_x = x.to_sparse_coo(sparse_dim=2)

        x.stop_gradient = False
        sparse_x.stop_gradient = False

        dense_out = self.dense(x)
        loss = dense_out.mean()
        loss.backward(retain_graph=True)

        sparse_out = self.sparse(sparse_x)
        sparse_loss = sparse_out.values().mean()
        sparse_loss.backward(retain_graph=True)

        np.testing.assert_allclose(
            dense_out.numpy(), sparse_out.to_dense().numpy()
        )
        np.testing.assert_allclose(
            x.grad.numpy(), sparse_x.grad.to_dense().numpy()
        )

        loss.backward()
        sparse_loss.backward()

        np.testing.assert_allclose(
            x.grad.numpy(), sparse_x.grad.to_dense().numpy()
        )


if __name__ == "__main__":
    unittest.main()