began work on v3

v3/classes/backbones.py

@@ -0,0 +1,178 @@
+# classes/backbones.py
+from __future__ import annotations
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Callable, Dict, List
+
+import torch
+from torch import nn
+from torchvision import models
+
+@dataclass(frozen=True)
+class BackboneSpec:
+    ctor: Callable                  # torchvision constructor
+    weights_default: object         # torchvision Weights enum DEFAULT member
+    strip: Callable[[nn.Module], tuple]   # fn(model)->(out_dim, model_no_head)
+    blocks: Callable[[nn.Module], List[nn.Module]]  # fn(model)->ordered blocks for freezing
+
+REFUGELIKE_BACKBONE_PATH = Path("models/v2/refuge/refugelike_backbone.pt")
+REFUGE_DENSENET_PATH = Path("models/refuge/classifier/refuge_densenet_backbone.pt")
+REFUGE_EFFICIENT_B0_PATH = Path("models/refuge/classifier/refuge_efficient_b0_backbone.pt")
+REFUGE_EFFICIENT_B7_PATH = Path("models/refuge/classifier/refuge_efficient_b7_backbone.pt")
+
+# --- strip fns ---
+def _strip_efficientnet_b0(m: models.EfficientNet):
+    from torch import nn as _nn
+    out_dim = m.classifier[1].in_features
+    m.classifier = _nn.Identity()
+    return out_dim, m
+
+def _strip_resnet(m: models.ResNet):
+    out_dim = m.fc.in_features
+    m.fc = nn.Identity()
+    return out_dim, m
+
+def _strip_densenet(m: models.DenseNet):
+    out_dim = m.classifier.in_features
+    m.classifier = nn.Identity()
+    return out_dim, m
+
+def _strip_vgg(m: models.VGG):
+    out_dim = m.classifier[0].in_features   # 25088 for VGG16 at 224×224
+    m.classifier = nn.Identity()
+    return out_dim, m
+
+def _strip_mobilenet_v2(m: models.MobileNetV2):
+    out_dim = m.classifier[1].in_features
+    m.classifier = nn.Identity()
+    return out_dim, m
+
+def _strip_inception_v3(m: models.Inception3):
+    out_dim = m.fc.in_features
+    m.fc = nn.Identity()
+    m.aux_logits = False
+    m.AuxLogits = None  # torchvision checks `AuxLogits is not None`, not the flag
+    return out_dim, m
+
+# --- block splitters for ratio-based freezing ---
+def _blocks_efficientnet_b0(m: models.EfficientNet):
+    return list(m.features)
+
+def _blocks_resnet(m: models.ResNet):
+    stem = nn.Sequential(m.conv1, m.bn1, m.relu, m.maxpool)
+    return [stem, m.layer1, m.layer2, m.layer3, m.layer4]
+
+def _blocks_densenet(m: models.DenseNet):
+    f = m.features
+    stem = nn.Sequential(f.conv0, f.norm0, f.relu0, f.pool0)
+    return [stem, f.denseblock1, f.transition1, f.denseblock2, f.transition2,
+            f.denseblock3, f.transition3, f.denseblock4, f.norm5]
+
+def _blocks_vgg(m: models.VGG):
+    stages, cur = [], []
+    for mod in m.features:
+        cur.append(mod)
+        if isinstance(mod, nn.MaxPool2d):
+            stages.append(nn.Sequential(*cur)); cur = []
+    if cur: stages.append(nn.Sequential(*cur))
+    return stages
+
+def _blocks_mobilenet_v2(m: models.MobileNetV2):
+    return list(m.features)
+
+def _blocks_inception_v3(m: models.Inception3):
+    blocks = []
+    for name, child in m.named_children():
+        if name in ("fc", "AuxLogits"):
+            continue
+        blocks.append(child)
+    return blocks
+
+# --- registry (covers paper models available in torchvision) ---
+BACKBONES: Dict[str, BackboneSpec] = {
+    "efficientnet_b0": BackboneSpec(
+        ctor=models.efficientnet_b0,
+        weights_default=models.EfficientNet_B0_Weights.DEFAULT,
+        strip=_strip_efficientnet_b0,
+        blocks=_blocks_efficientnet_b0,
+    ),
+    "resnet50": BackboneSpec(
+        ctor=models.resnet50,
+        weights_default=models.ResNet50_Weights.DEFAULT,
+        strip=_strip_resnet,
+        blocks=_blocks_resnet,
+    ),
+    "densenet121": BackboneSpec(
+        ctor=models.densenet121,
+        weights_default=models.DenseNet121_Weights.DEFAULT,
+        strip=_strip_densenet,
+        blocks=_blocks_densenet,
+    ),
+    "vgg16": BackboneSpec(
+        ctor=models.vgg16,
+        weights_default=models.VGG16_Weights.DEFAULT,
+        strip=_strip_vgg,
+        blocks=_blocks_vgg,
+    ),
+    "mobilenet_v2": BackboneSpec(
+        ctor=models.mobilenet_v2,
+        weights_default=models.MobileNet_V2_Weights.DEFAULT,
+        strip=_strip_mobilenet_v2,
+        blocks=_blocks_mobilenet_v2,
+    ),
+    "inception_v3": BackboneSpec(
+        ctor=models.inception_v3,
+        weights_default=models.Inception_V3_Weights.DEFAULT,
+        strip=_strip_inception_v3,
+        blocks=_blocks_inception_v3,
+    ),
+    "refugelike": BackboneSpec(
+        ctor=models.resnet50,
+        weights_default=None,
+        strip=_strip_resnet,
+        blocks=_blocks_resnet,
+    ),
+    "refuge_densenet": BackboneSpec(
+        ctor=models.densenet121,
+        weights_default=None,
+        strip=_strip_densenet,
+        blocks=_blocks_densenet,
+    ),
+    "refuge_efficient_b0": BackboneSpec(
+        ctor=models.efficientnet_b0,
+        weights_default=None,
+        strip=_strip_efficientnet_b0,
+        blocks=_blocks_efficientnet_b0,
+    ),
+    "refuge_efficient_b7": BackboneSpec(
+        ctor=models.efficientnet_b7,
+        weights_default=None,
+        strip=_strip_efficientnet_b0,
+        blocks=_blocks_efficientnet_b0,
+    ),
+    # Xception isn’t in torchvision 
+}
+
+def list_names() -> List[str]:
+    return list(BACKBONES.keys())
+    
+
+def load_backbone_weights(key: str, model: nn.Module) -> None:
+    if key == "refugelike":
+        path = REFUGELIKE_BACKBONE_PATH
+    elif key == "refuge_densenet":
+        path = REFUGE_DENSENET_PATH
+    elif key == "refuge_efficient_b0":
+        path = REFUGE_EFFICIENT_B0_PATH
+    elif key == "refuge_efficient_b7":
+        path = REFUGE_EFFICIENT_B7_PATH
+    else:
+        return
+
+    if not path.exists():
+        raise FileNotFoundError(
+            "Custom REFUGE backbone not found at "
+            f"{path}. Export it via refuge_build.py --export-backbone first."
+        )
+    state = torch.load(path, map_location="cpu")
+    model.load_state_dict(state, strict=False)