functional.py

'''
Script provides functional interface for Mish activation function.
'''

# import pytorch
import torch
import torch.nn.functional as F

def mish(input):
    '''
    Applies the mish function element-wise:
    mish(x) = x * tanh(softplus(x)) = x * tanh(ln(1 + exp(x)))
    See additional documentation for mish class.
    '''
    return input * torch.tanh(F.softplus(input))