#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Copyright 2020 Johns Hopkins University (Shinji Watanabe)
#                Northwestern Polytechnical University (Pengcheng Guo)
#  Apache 2.0  (http://www.apache.org/licenses/LICENSE-2.0)

"""Swish() activation function for Conformer."""

import torch


class Swish(torch.nn.Module):
    """Construct an Swish object."""

    def forward(self, x):
        """Return Swich activation function."""
        return x * torch.sigmoid(x)