# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.

import torch
import torch.nn as nn
from mmengine.registry import MODELS


@MODELS.register_module()
class Swish(nn.Module):
    """Swish Module.

    This module applies the swish function:

    .. math::
        Swish(x) = x * Sigmoid(x)

    Returns:
        Tensor: The output tensor.
    """

    def __init__(self):
        super().__init__()

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        return x * torch.sigmoid(x)