From f4cf9775c35b5c3ce8c2470ed151e48d663b1e79 Mon Sep 17 00:00:00 2001
From: Ross Wightman <rwightman@gmail.com>
Date: Mon, 21 Aug 2023 12:28:34 -0700
Subject: [PATCH] Adding InceptionNeXt

---
 timm/models/__init__.py       |   1 +
 timm/models/inception_next.py | 374 ++++++++++++++++++++++++++++++++++
 2 files changed, 375 insertions(+)
 create mode 100644 timm/models/inception_next.py

diff --git a/timm/models/__init__.py b/timm/models/__init__.py
index 1c255359..18828a5a 100644
--- a/timm/models/__init__.py
+++ b/timm/models/__init__.py
@@ -26,6 +26,7 @@ from .gcvit import *
 from .ghostnet import *
 from .hardcorenas import *
 from .hrnet import *
+from .inception_next import *
 from .inception_resnet_v2 import *
 from .inception_v3 import *
 from .inception_v4 import *
diff --git a/timm/models/inception_next.py b/timm/models/inception_next.py
new file mode 100644
index 00000000..f51161ae
--- /dev/null
+++ b/timm/models/inception_next.py
@@ -0,0 +1,374 @@
+"""
+InceptionNeXt implementation, paper: https://arxiv.org/abs/2303.16900
+
+Some code is borrowed from timm: https://github.com/huggingface/pytorch-image-models
+"""
+
+from functools import partial
+
+import torch
+import torch.nn as nn
+
+from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
+from timm.layers import trunc_normal_, DropPath, to_2tuple
+from ._manipulate import checkpoint_seq
+from ._registry import register_model
+
+
+class InceptionDWConv2d(nn.Module):
+    """ Inception depthweise convolution
+    """
+
+    def __init__(self, in_channels, square_kernel_size=3, band_kernel_size=11, branch_ratio=0.125):
+        super().__init__()
+
+        gc = int(in_channels * branch_ratio)  # channel numbers of a convolution branch
+        self.dwconv_hw = nn.Conv2d(gc, gc, square_kernel_size, padding=square_kernel_size // 2, groups=gc)
+        self.dwconv_w = nn.Conv2d(
+            gc, gc, kernel_size=(1, band_kernel_size), padding=(0, band_kernel_size // 2), groups=gc)
+        self.dwconv_h = nn.Conv2d(
+            gc, gc, kernel_size=(band_kernel_size, 1), padding=(band_kernel_size // 2, 0), groups=gc)
+        self.split_indexes = (in_channels - 3 * gc, gc, gc, gc)
+
+    def forward(self, x):
+        x_id, x_hw, x_w, x_h = torch.split(x, self.split_indexes, dim=1)
+        return torch.cat((
+            x_id,
+            self.dwconv_hw(x_hw),
+            self.dwconv_w(x_w),
+            self.dwconv_h(x_h)
+            ), dim=1,
+        )
+
+
+class ConvMlp(nn.Module):
+    """ MLP using 1x1 convs that keeps spatial dims
+    copied from timm: https://github.com/huggingface/pytorch-image-models/blob/v0.6.11/timm/models/layers/mlp.py
+    """
+
+    def __init__(
+            self, in_features, hidden_features=None, out_features=None, act_layer=nn.ReLU,
+            norm_layer=None, bias=True, drop=0.):
+        super().__init__()
+        out_features = out_features or in_features
+        hidden_features = hidden_features or in_features
+        bias = to_2tuple(bias)
+
+        self.fc1 = nn.Conv2d(in_features, hidden_features, kernel_size=1, bias=bias[0])
+        self.norm = norm_layer(hidden_features) if norm_layer else nn.Identity()
+        self.act = act_layer()
+        self.drop = nn.Dropout(drop)
+        self.fc2 = nn.Conv2d(hidden_features, out_features, kernel_size=1, bias=bias[1])
+
+    def forward(self, x):
+        x = self.fc1(x)
+        x = self.norm(x)
+        x = self.act(x)
+        x = self.drop(x)
+        x = self.fc2(x)
+        return x
+
+
+class MlpHead(nn.Module):
+    """ MLP classification head
+    """
+
+    def __init__(
+            self, dim, num_classes=1000, mlp_ratio=3, act_layer=nn.GELU,
+            norm_layer=partial(nn.LayerNorm, eps=1e-6), drop=0., bias=True):
+        super().__init__()
+        hidden_features = int(mlp_ratio * dim)
+        self.fc1 = nn.Linear(dim, hidden_features, bias=bias)
+        self.act = act_layer()
+        self.norm = norm_layer(hidden_features)
+        self.fc2 = nn.Linear(hidden_features, num_classes, bias=bias)
+        self.drop = nn.Dropout(drop)
+
+    def forward(self, x):
+        x = x.mean((2, 3))  # global average pooling
+        x = self.fc1(x)
+        x = self.act(x)
+        x = self.norm(x)
+        x = self.drop(x)
+        x = self.fc2(x)
+        return x
+
+
+class MetaNeXtBlock(nn.Module):
+    """ MetaNeXtBlock Block
+    Args:
+        dim (int): Number of input channels.
+        drop_path (float): Stochastic depth rate. Default: 0.0
+        ls_init_value (float): Init value for Layer Scale. Default: 1e-6.
+    """
+
+    def __init__(
+            self,
+            dim,
+            token_mixer=nn.Identity,
+            norm_layer=nn.BatchNorm2d,
+            mlp_layer=ConvMlp,
+            mlp_ratio=4,
+            act_layer=nn.GELU,
+            ls_init_value=1e-6,
+            drop_path=0.,
+
+    ):
+        super().__init__()
+        self.token_mixer = token_mixer(dim)
+        self.norm = norm_layer(dim)
+        self.mlp = mlp_layer(dim, int(mlp_ratio * dim), act_layer=act_layer)
+        self.gamma = nn.Parameter(ls_init_value * torch.ones(dim)) if ls_init_value else None
+        self.drop_path = DropPath(drop_path) if drop_path > 0. else nn.Identity()
+
+    def forward(self, x):
+        shortcut = x
+        x = self.token_mixer(x)
+        x = self.norm(x)
+        x = self.mlp(x)
+        if self.gamma is not None:
+            x = x.mul(self.gamma.reshape(1, -1, 1, 1))
+        x = self.drop_path(x) + shortcut
+        return x
+
+
+class MetaNeXtStage(nn.Module):
+    def __init__(
+            self,
+            in_chs,
+            out_chs,
+            ds_stride=2,
+            depth=2,
+            drop_path_rates=None,
+            ls_init_value=1.0,
+            token_mixer=nn.Identity,
+            act_layer=nn.GELU,
+            norm_layer=None,
+            mlp_ratio=4,
+    ):
+        super().__init__()
+        self.grad_checkpointing = False
+        if ds_stride > 1:
+            self.downsample = nn.Sequential(
+                norm_layer(in_chs),
+                nn.Conv2d(in_chs, out_chs, kernel_size=ds_stride, stride=ds_stride),
+            )
+        else:
+            self.downsample = nn.Identity()
+
+        drop_path_rates = drop_path_rates or [0.] * depth
+        stage_blocks = []
+        for i in range(depth):
+            stage_blocks.append(MetaNeXtBlock(
+                dim=out_chs,
+                drop_path=drop_path_rates[i],
+                ls_init_value=ls_init_value,
+                token_mixer=token_mixer,
+                act_layer=act_layer,
+                norm_layer=norm_layer,
+                mlp_ratio=mlp_ratio,
+            ))
+            in_chs = out_chs
+        self.blocks = nn.Sequential(*stage_blocks)
+
+    def forward(self, x):
+        x = self.downsample(x)
+        if self.grad_checkpointing and not torch.jit.is_scripting():
+            x = checkpoint_seq(self.blocks, x)
+        else:
+            x = self.blocks(x)
+        return x
+
+
+class MetaNeXt(nn.Module):
+    r""" MetaNeXt
+        A PyTorch impl of : `InceptionNeXt: When Inception Meets ConvNeXt`  - https://arxiv.org/pdf/2203.xxxxx.pdf
+
+    Args:
+        in_chans (int): Number of input image channels. Default: 3
+        num_classes (int): Number of classes for classification head. Default: 1000
+        depths (tuple(int)): Number of blocks at each stage. Default: (3, 3, 9, 3)
+        dims (tuple(int)): Feature dimension at each stage. Default: (96, 192, 384, 768)
+        token_mixers: Token mixer function. Default: nn.Identity
+        norm_layer: Normalziation layer. Default: nn.BatchNorm2d
+        act_layer: Activation function for MLP. Default: nn.GELU
+        mlp_ratios (int or tuple(int)): MLP ratios. Default: (4, 4, 4, 3)
+        head_fn: classifier head
+        drop_rate (float): Head dropout rate
+        drop_path_rate (float): Stochastic depth rate. Default: 0.
+        ls_init_value (float): Init value for Layer Scale. Default: 1e-6.
+    """
+
+    def __init__(
+            self,
+            in_chans=3,
+            num_classes=1000,
+            depths=(3, 3, 9, 3),
+            dims=(96, 192, 384, 768),
+            token_mixers=nn.Identity,
+            norm_layer=nn.BatchNorm2d,
+            act_layer=nn.GELU,
+            mlp_ratios=(4, 4, 4, 3),
+            head_fn=MlpHead,
+            drop_rate=0.,
+            drop_path_rate=0.,
+            ls_init_value=1e-6,
+            **kwargs,
+    ):
+        super().__init__()
+
+        num_stage = len(depths)
+        if not isinstance(token_mixers, (list, tuple)):
+            token_mixers = [token_mixers] * num_stage
+        if not isinstance(mlp_ratios, (list, tuple)):
+            mlp_ratios = [mlp_ratios] * num_stage
+
+        self.num_classes = num_classes
+        self.drop_rate = drop_rate
+        self.stem = nn.Sequential(
+            nn.Conv2d(in_chans, dims[0], kernel_size=4, stride=4),
+            norm_layer(dims[0])
+        )
+
+        self.stages = nn.Sequential()
+        dp_rates = [x.tolist() for x in torch.linspace(0, drop_path_rate, sum(depths)).split(depths)]
+        stages = []
+        prev_chs = dims[0]
+        # feature resolution stages, each consisting of multiple residual blocks
+        for i in range(num_stage):
+            out_chs = dims[i]
+            stages.append(MetaNeXtStage(
+                prev_chs,
+                out_chs,
+                ds_stride=2 if i > 0 else 1,
+                depth=depths[i],
+                drop_path_rates=dp_rates[i],
+                ls_init_value=ls_init_value,
+                act_layer=act_layer,
+                token_mixer=token_mixers[i],
+                norm_layer=norm_layer,
+                mlp_ratio=mlp_ratios[i],
+            ))
+            prev_chs = out_chs
+        self.stages = nn.Sequential(*stages)
+        self.num_features = prev_chs
+        self.head = head_fn(self.num_features, num_classes, drop=drop_rate)
+        self.apply(self._init_weights)
+
+    @torch.jit.ignore
+    def set_grad_checkpointing(self, enable=True):
+        for s in self.stages:
+            s.grad_checkpointing = enable
+
+    @torch.jit.ignore
+    def no_weight_decay(self):
+        return {'norm'}
+
+    def forward_features(self, x):
+        x = self.stem(x)
+        x = self.stages(x)
+        return x
+
+    def forward_head(self, x):
+        x = self.head(x)
+        return x
+
+    def forward(self, x):
+        x = self.forward_features(x)
+        x = self.forward_head(x)
+        return x
+
+    def _init_weights(self, m):
+        if isinstance(m, (nn.Conv2d, nn.Linear)):
+            trunc_normal_(m.weight, std=.02)
+            if m.bias is not None:
+                nn.init.constant_(m.bias, 0)
+
+
+def _cfg(url='', **kwargs):
+    return {
+        'url': url,
+        'num_classes': 1000, 'input_size': (3, 224, 224), 'pool_size': (7, 7),
+        'crop_pct': 0.875, 'interpolation': 'bicubic',
+        'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD,
+        'first_conv': 'stem.0', 'classifier': 'head.fc',
+        **kwargs
+    }
+
+
+default_cfgs = dict(
+    inception_next_tiny=_cfg(
+        url='https://github.com/sail-sg/inceptionnext/releases/download/model/inceptionnext_tiny.pth',
+    ),
+    inception_next_small=_cfg(
+        url='https://github.com/sail-sg/inceptionnext/releases/download/model/inceptionnext_small.pth',
+    ),
+    inception_next_base=_cfg(
+        url='https://github.com/sail-sg/inceptionnext/releases/download/model/inceptionnext_base.pth',
+    ),
+    inception_next_base_384=_cfg(
+        url='https://github.com/sail-sg/inceptionnext/releases/download/model/inceptionnext_base_384.pth',
+        input_size=(3, 384, 384), crop_pct=1.0,
+    ),
+)
+
+
+@register_model
+def inception_next_tiny(pretrained=False, **kwargs):
+    model = MetaNeXt(
+        depths=(3, 3, 9, 3), dims=(96, 192, 384, 768),
+        token_mixers=InceptionDWConv2d,
+        **kwargs
+    )
+    model.default_cfg = default_cfgs['inception_next_tiny']
+    if pretrained:
+        state_dict = torch.hub.load_state_dict_from_url(
+            url=model.default_cfg['url'], map_location="cpu", check_hash=True)
+        model.load_state_dict(state_dict)
+    return model
+
+
+@register_model
+def inception_next_small(pretrained=False, **kwargs):
+    model = MetaNeXt(
+        depths=(3, 3, 27, 3), dims=(96, 192, 384, 768),
+        token_mixers=InceptionDWConv2d,
+        **kwargs
+    )
+    model.default_cfg = default_cfgs['inception_next_small']
+    if pretrained:
+        state_dict = torch.hub.load_state_dict_from_url(
+            url=model.default_cfg['url'], map_location="cpu", check_hash=True)
+        model.load_state_dict(state_dict)
+    return model
+
+
+@register_model
+def inception_next_base(pretrained=False, **kwargs):
+    model = MetaNeXt(
+        depths=(3, 3, 27, 3), dims=(128, 256, 512, 1024),
+        token_mixers=InceptionDWConv2d,
+        **kwargs
+    )
+    model.default_cfg = default_cfgs['inception_next_base']
+    if pretrained:
+        state_dict = torch.hub.load_state_dict_from_url(
+            url=model.default_cfg['url'], map_location="cpu", check_hash=True)
+        model.load_state_dict(state_dict)
+    return model
+
+
+@register_model
+def inception_next_base_384(pretrained=False, **kwargs):
+    model = MetaNeXt(
+        depths=[3, 3, 27, 3], dims=[128, 256, 512, 1024],
+        mlp_ratios=[4, 4, 4, 3],
+        token_mixers=InceptionDWConv2d,
+        **kwargs
+    )
+    model.default_cfg = default_cfgs['inception_next_base_384']
+    if pretrained:
+        state_dict = torch.hub.load_state_dict_from_url(
+            url=model.default_cfg['url'], map_location="cpu", check_hash=True)
+        model.load_state_dict(state_dict)
+    return model