1 files changed, 143 insertions, 0 deletions
diff --git a/text_recognizer/networks/encoders/efficient_net/block.py b/text_recognizer/networks/encoders/efficient_net/block.py
new file mode 100644
index 0000000..4302bbd
--- /dev/null
+++ b/text_recognizer/networks/encoders/efficient_net/block.py
@@ -0,0 +1,143 @@
+"""Mobile inverted residual block."""
+from typing import Tuple
+
+import torch
+from torch import nn, Tensor
+
+from .utils import get_same_padding_conv2d
+
+
+class MBConvBlock(nn.Module):
+    """Mobile Inverted Residual Bottleneck block."""
+
+    def __init__(
+        self,
+        in_channels: int,
+        kernel_size: int,
+        stride: int,
+        bn_momentum: float,
+        bn_eps: float,
+        se_ratio: float,
+        id_skip: bool,
+        expand_ratio: int,
+        image_size: Tuple[int, int],
+    ) -> None:
+        super().__init__()
+        self.kernel_size = kernel_size
+        self.bn_momentum = bn_momentum
+        self.bn_eps = bn_eps
+        self.has_se = se_ratio is not None and 0.0 < se_ratio < 1.0
+
+        out_channels = in_channels * expand_ratio
+        self._inverted_bottleneck = (
+            self._configure_inverted_bottleneck(
+                image_size=image_size,
+                in_channels=in_channels,
+                out_channels=out_channels,
+            )
+            if expand_ratio != 1
+            else None
+        )
+
+        self._depthwise = self._configure_depthwise(
+            image_size=image_size,
+            in_channels=in_channels,
+            out_channels=out_channels,
+            groups=out_channels,
+            kernel_size=kernel_size,
+            stride=stride,
+        )
+
+        image_size = calculate_output_image_size(image_size, stride)
+        self._squeeze_excite = (
+            self._configure_squeeze_excite(
+                in_channels=out_channels, out_channels=out_channels, se_ratio=se_ratio
+            )
+            if self.has_se
+            else None
+        )
+
+        self._pointwise = self._configure_pointwise(
+            image_size=image_size, in_channels=out_channels, out_channels=out_channels
+        )
+
+    def _configure_inverted_bottleneck(
+        self,
+        image_size: Tuple[int, int],
+        in_channels: int,
+        out_channels: int,
+    ) -> nn.Sequential:
+        """Expansion phase."""
+        Conv2d = get_same_padding_conv2d(image_size=image_size)
+        return nn.Sequential(
+            Conv2d(
+                in_channels=in_channels,
+                out_channels=out_channels,
+                kernel_size=1,
+                bias=False,
+            ),
+            nn.BatchNorm2d(
+                num_features=out_channels, momentum=self.bn_momentum, eps=self.bn_eps
+            ),
+            nn.SiLU(inplace=True),
+        )
+
+    def _configure_depthwise(
+        self,
+        image_size: Tuple[int, int],
+        in_channels: int,
+        out_channels: int,
+        groups: int,
+        kernel_size: int,
+        stride: int,
+    ) -> nn.Sequential:
+        Conv2d = get_same_padding_conv2d(image_size=image_size)
+        return nn.Sequential(
+            Conv2d(
+                in_channels=in_channels,
+                out_channels=out_channels,
+                kernel_size=kernel_size,
+                stride=stride,
+                groups=groups,
+                bias=False,
+            ),
+            nn.BatchNorm2d(
+                num_features=out_channels, momentum=self.bn_momentum, eps=self.bn_eps
+            ),
+            nn.SiLU(inplace=True),
+        )
+
+    def _configure_squeeze_excite(
+        self, in_channels: int, out_channels: int, se_ratio: float
+    ) -> nn.Sequential:
+        Conv2d = get_same_padding_conv2d(image_size=(1, 1))
+        num_squeezed_channels = max(1, int(in_channels * se_ratio))
+        return nn.Sequential(
+            Conv2d(
+                in_channels=in_channels,
+                out_channels=num_squeezed_channels,
+                kernel_size=1,
+            ),
+            nn.SiLU(inplace=True),
+            Conv2d(
+                in_channels=num_squeezed_channels,
+                out_channels=out_channels,
+                kernel_size=1,
+            ),
+        )
+
+    def _configure_pointwise(
+        self, image_size: Tuple[int, int], in_channels: int, out_channels: int
+    ) -> nn.Sequential:
+        Conv2d = get_same_padding_conv2d(image_size=image_size)
+        return nn.Sequential(
+            Conv2d(
+                in_channels=in_channels,
+                out_channels=out_channels,
+                kernel_size=1,
+                bias=False,
+            ),
+            nn.BatchNorm2d(
+                num_features=out_channels, momentum=self.bn_momentum, eps=self.bn_eps
+            ),
+        )