Stable3DGen/hi3dgen/modules/norm.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


class LayerNorm32(nn.LayerNorm):
    def forward(self, x: torch.Tensor) -> torch.Tensor:
        return super().forward(x.float()).type(x.dtype)
    

class GroupNorm32(nn.GroupNorm):
    """
    A GroupNorm layer that converts to float32 before the forward pass.
    """
    def forward(self, x: torch.Tensor) -> torch.Tensor:
        return super().forward(x.float()).type(x.dtype)
    
    
class ChannelLayerNorm32(LayerNorm32):
    def forward(self, x: torch.Tensor) -> torch.Tensor:
        DIM = x.dim()
        x = x.permute(0, *range(2, DIM), 1).contiguous()
        x = super().forward(x)
        x = x.permute(0, DIM-1, *range(1, DIM-1)).contiguous()
        return x