Stable3DGen/hi3dgen/modules/sparse/nonlinearity.py

# MIT License

# Copyright (c) Microsoft

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# Copyright (c) [2025] [Microsoft]
# SPDX-License-Identifier: MIT
import torch
import torch.nn as nn
from . import SparseTensor

__all__ = [
    'SparseReLU',
    'SparseSiLU',
    'SparseGELU',
    'SparseActivation'
]


class SparseReLU(nn.ReLU):
    def forward(self, input: SparseTensor) -> SparseTensor:
        return input.replace(super().forward(input.feats))
    

class SparseSiLU(nn.SiLU):
    def forward(self, input: SparseTensor) -> SparseTensor:
        return input.replace(super().forward(input.feats))


class SparseGELU(nn.GELU):
    def forward(self, input: SparseTensor) -> SparseTensor:
        return input.replace(super().forward(input.feats))


class SparseActivation(nn.Module):
    def __init__(self, activation: nn.Module):
        super().__init__()
        self.activation = activation

    def forward(self, input: SparseTensor) -> SparseTensor:
        return input.replace(self.activation(input.feats))