One codepath for stdconv, switch layernorm to batchnorm so gain included. Tweak epsilon values for nfnet, resnetv2, vit hybrid.

Author: rwightman

timm/models/layers/std_conv.py

@@ -18,27 +18,20 @@ class StdConv2d(nn.Conv2d):
         https://arxiv.org/abs/1903.10520v2
     """
     def __init__(
-            self, in_channel, out_channels, kernel_size, stride=1, padding=None, dilation=1,
-            groups=1, bias=False, eps=1e-5, use_layernorm=True):
+            self, in_channel, out_channels, kernel_size, stride=1, padding=None,
+            dilation=1, groups=1, bias=False, eps=1e-6):
         if padding is None:
             padding = get_padding(kernel_size, stride, dilation)
         super().__init__(
             in_channel, out_channels, kernel_size, stride=stride,
             padding=padding, dilation=dilation, groups=groups, bias=bias)
         self.eps = eps
-        self.use_layernorm = use_layernorm
-
-    def get_weight(self):
-        if self.use_layernorm:
-            # NOTE F.layer_norm is being used to compute (self.weight - mean) / (sqrt(var) + self.eps) in one op
-            weight = F.layer_norm(self.weight, self.weight.shape[1:], eps=self.eps)
-        else:
-            std, mean = torch.std_mean(self.weight, dim=[1, 2, 3], keepdim=True, unbiased=False)
-            weight = (self.weight - mean) / (std + self.eps)
-        return weight
 
     def forward(self, x):
-        x = F.conv2d(x, self.get_weight(), self.bias, self.stride, self.padding, self.dilation, self.groups)
+        weight = F.batch_norm(
+            self.weight.view(1, self.out_channels, -1), None, None,
+            eps=self.eps, training=True, momentum=0.).reshape_as(self.weight)
+        x = F.conv2d(x, weight, self.bias, self.stride, self.padding, self.dilation, self.groups)
         return x
 
 
@@ -49,29 +42,22 @@ class StdConv2dSame(nn.Conv2d):
         https://arxiv.org/abs/1903.10520v2
     """
     def __init__(
-            self, in_channel, out_channels, kernel_size, stride=1, padding='SAME', dilation=1,
-            groups=1, bias=False, eps=1e-5, use_layernorm=True):
+            self, in_channel, out_channels, kernel_size, stride=1, padding='SAME',
+            dilation=1, groups=1, bias=False, eps=1e-6):
         padding, is_dynamic = get_padding_value(padding, kernel_size, stride=stride, dilation=dilation)
         super().__init__(
             in_channel, out_channels, kernel_size, stride=stride, padding=padding, dilation=dilation,
             groups=groups, bias=bias)
         self.same_pad = is_dynamic
         self.eps = eps
-        self.use_layernorm = use_layernorm
-
-    def get_weight(self):
-        if self.use_layernorm:
-            # NOTE F.layer_norm is being used to compute (self.weight - mean) / (sqrt(var) + self.eps) in one op
-            weight = F.layer_norm(self.weight, self.weight.shape[1:], eps=self.eps)
-        else:
-            std, mean = torch.std_mean(self.weight, dim=[1, 2, 3], keepdim=True, unbiased=False)
-            weight = (self.weight - mean) / (std + self.eps)
-        return weight
 
     def forward(self, x):
         if self.same_pad:
             x = pad_same(x, self.kernel_size, self.stride, self.dilation)
-        x = F.conv2d(x, self.get_weight(), self.bias, self.stride, self.padding, self.dilation, self.groups)
+        weight = F.batch_norm(
+            self.weight.view(1, self.out_channels, -1), None, None,
+            eps=self.eps, training=True, momentum=0.).reshape_as(self.weight)
+        x = F.conv2d(x, weight, self.bias, self.stride, self.padding, self.dilation, self.groups)
         return x
 
 
@@ -85,8 +71,8 @@ class ScaledStdConv2d(nn.Conv2d):
     """
 
     def __init__(
-            self, in_channels, out_channels, kernel_size, stride=1, padding=None, dilation=1, groups=1,
-            bias=True, gamma=1.0, eps=1e-5, gain_init=1.0, use_layernorm=True):
+            self, in_channels, out_channels, kernel_size, stride=1, padding=None,
+            dilation=1, groups=1, bias=True, gamma=1.0, eps=1e-6, gain_init=1.0):
         if padding is None:
             padding = get_padding(kernel_size, stride, dilation)
         super().__init__(
@@ -95,19 +81,13 @@ def __init__(
         self.gain = nn.Parameter(torch.full((self.out_channels, 1, 1, 1), gain_init))
         self.scale = gamma * self.weight[0].numel() ** -0.5  # gamma * 1 / sqrt(fan-in)
         self.eps = eps
-        self.use_layernorm = use_layernorm  # experimental, slightly faster/less GPU memory to hijack LN kernel
-
-    def get_weight(self):
-        if self.use_layernorm:
-            # NOTE F.layer_norm is being used to compute (self.weight - mean) / (sqrt(var) + self.eps) in one op
-            weight = F.layer_norm(self.weight, self.weight.shape[1:], eps=self.eps)
-        else:
-            std, mean = torch.std_mean(self.weight, dim=[1, 2, 3], keepdim=True, unbiased=False)
-            weight = (self.weight - mean) / (std + self.eps)
-        return weight.mul_(self.gain * self.scale)
 
     def forward(self, x):
-        return F.conv2d(x, self.get_weight(), self.bias, self.stride, self.padding, self.dilation, self.groups)
+        weight = F.batch_norm(
+            self.weight.view(1, self.out_channels, -1), None, None,
+            weight=(self.gain * self.scale).view(-1),
+            eps=self.eps, training=True, momentum=0.).reshape_as(self.weight)
+        return F.conv2d(x, weight, self.bias, self.stride, self.padding, self.dilation, self.groups)
 
 
 class ScaledStdConv2dSame(nn.Conv2d):
@@ -120,8 +100,8 @@ class ScaledStdConv2dSame(nn.Conv2d):
     """
 
     def __init__(
-            self, in_channels, out_channels, kernel_size, stride=1, padding='SAME', dilation=1, groups=1,
-            bias=True, gamma=1.0, eps=1e-5, gain_init=1.0, use_layernorm=True):
+            self, in_channels, out_channels, kernel_size, stride=1, padding='SAME',
+            dilation=1, groups=1, bias=True, gamma=1.0, eps=1e-6, gain_init=1.0):
         padding, is_dynamic = get_padding_value(padding, kernel_size, stride=stride, dilation=dilation)
         super().__init__(
             in_channels, out_channels, kernel_size, stride=stride, padding=padding, dilation=dilation,
@@ -130,18 +110,12 @@ def __init__(
         self.scale = gamma * self.weight[0].numel() ** -0.5
         self.same_pad = is_dynamic
         self.eps = eps
-        self.use_layernorm = use_layernorm  # experimental, slightly faster/less GPU memory to hijack LN kernel
-
-    def get_weight(self):
-        if self.use_layernorm:
-            # NOTE F.layer_norm is being used to compute (self.weight - mean) / (sqrt(var) + self.eps) in one op
-            weight = F.layer_norm(self.weight, self.weight.shape[1:], eps=self.eps)
-        else:
-            std, mean = torch.std_mean(self.weight, dim=[1, 2, 3], keepdim=True, unbiased=False)
-            weight = (self.weight - mean) / (std + self.eps)
-        return weight.mul_(self.gain * self.scale)
 
     def forward(self, x):
         if self.same_pad:
             x = pad_same(x, self.kernel_size, self.stride, self.dilation)
-        return F.conv2d(x, self.get_weight(), self.bias, self.stride, self.padding, self.dilation, self.groups)
+        weight = F.batch_norm(
+            self.weight.view(1, self.out_channels, -1), None, None,
+            weight=(self.gain * self.scale).view(-1),
+            eps=self.eps, training=True, momentum=0.).reshape_as(self.weight)
+        return F.conv2d(x, weight, self.bias, self.stride, self.padding, self.dilation, self.groups)

timm/models/nfnet.py

@@ -167,7 +167,6 @@ class NfCfg:
     gamma_in_act: bool = False
     same_padding: bool = False
     std_conv_eps: float = 1e-5
-    std_conv_ln: bool = True  # use layer-norm impl to normalize in std-conv, works in PyTorch XLA, slightly faster
     skipinit: bool = False  # disabled by default, non-trivial performance impact
     zero_init_fc: bool = False
     act_layer: str = 'silu'
@@ -484,11 +483,10 @@ def __init__(self, cfg: NfCfg, num_classes=1000, in_chans=3, global_pool='avg',
         conv_layer = ScaledStdConv2dSame if cfg.same_padding else ScaledStdConv2d
         if cfg.gamma_in_act:
             act_layer = act_with_gamma(cfg.act_layer, gamma=_nonlin_gamma[cfg.act_layer])
-            conv_layer = partial(conv_layer, eps=cfg.std_conv_eps, use_layernorm=cfg.std_conv_ln)
+            conv_layer = partial(conv_layer, eps=cfg.std_conv_eps)
         else:
             act_layer = get_act_layer(cfg.act_layer)
-            conv_layer = partial(
-                conv_layer, gamma=_nonlin_gamma[cfg.act_layer], eps=cfg.std_conv_eps, use_layernorm=cfg.std_conv_ln)
+            conv_layer = partial(conv_layer, gamma=_nonlin_gamma[cfg.act_layer], eps=cfg.std_conv_eps)
         attn_layer = partial(get_attn(cfg.attn_layer), **cfg.attn_kwargs) if cfg.attn_layer else None
 
         stem_chs = make_divisible((cfg.stem_chs or cfg.channels[0]) * cfg.width_factor, cfg.ch_div)

timm/models/resnetv2.py

@@ -276,7 +276,7 @@ def forward(self, x):
 
 def create_resnetv2_stem(
         in_chs, out_chs=64, stem_type='', preact=True,
-        conv_layer=StdConv2d, norm_layer=partial(GroupNormAct, num_groups=32)):
+        conv_layer=partial(StdConv2d, eps=1e-8), norm_layer=partial(GroupNormAct, num_groups=32)):
     stem = OrderedDict()
     assert stem_type in ('', 'fixed', 'same', 'deep', 'deep_fixed', 'deep_same')
 
@@ -315,8 +315,8 @@ class ResNetV2(nn.Module):
     def __init__(self, layers, channels=(256, 512, 1024, 2048),
                  num_classes=1000, in_chans=3, global_pool='avg', output_stride=32,
                  width_factor=1, stem_chs=64, stem_type='', avg_down=False, preact=True,
-                 act_layer=nn.ReLU, conv_layer=StdConv2d, norm_layer=partial(GroupNormAct, num_groups=32),
-                 drop_rate=0., drop_path_rate=0.):
+                 act_layer=nn.ReLU, conv_layer=partial(StdConv2d, eps=1e-8),
+                 norm_layer=partial(GroupNormAct, num_groups=32), drop_rate=0., drop_path_rate=0.):
         super().__init__()
         self.num_classes = num_classes
         self.drop_rate = drop_rate

timm/models/vision_transformer_hybrid.py

@@ -116,12 +116,8 @@ def _create_vision_transformer_hybrid(variant, backbone, pretrained=False, **kwa
 def _resnetv2(layers=(3, 4, 9), **kwargs):
     """ ResNet-V2 backbone helper"""
     padding_same = kwargs.get('padding_same', True)
-    if padding_same:
-        stem_type = 'same'
-        conv_layer = partial(StdConv2dSame, eps=1e-5)
-    else:
-        stem_type = ''
-        conv_layer = StdConv2d
+    stem_type = 'same' if padding_same else ''
+    conv_layer = partial(StdConv2dSame, eps=1e-8) if padding_same else partial(StdConv2d, eps=1e-8)
     if len(layers):
         backbone = ResNetV2(
             layers=layers, num_classes=0, global_pool='', in_chans=kwargs.get('in_chans', 3),