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README.md

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+---
+license: bsd-3-clause
+tags:
+- base
+- contrastive
+- cross-attention
+- exponential
+- instancenorm
+- linear
+- orthogonal
+- relu
+- sgd
+- tiny-transformer
+---
+
+# model_311813953_tiny_transformer_base.py
+
+## Model Overview
+
+A **base**-scale implementation of the **tiny transformer** architecture, built for **contrastive** tasks.
+
+## Architecture
+
+- **Architecture**: tiny transformer
+- **Scale**: base
+- **Attention**: linear
+- **Fusion strategy**: cross attention
+- **Task head**: contrastive
+- **Activation**: relu
+- **Normalization**: instancenorm
+- **Initialization**: orthogonal
+
+## Training
+
+- **Optimizer**: sgd
+- **LR scheduler**: exponential
+
+## Files
+
+- `model_311813953_tiny_transformer_base.py` — main artifact of this repository
+
+## License
+
+See the license field above.

model_311813953_tiny_transformer_base.py

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+import torch
+import torch.nn as nn
+import math
+
+
+class TinyTransformerModel(nn.Module):
+    '''
+    tiny_transformer model with linear attention.
+    Scale: base (dim=256, layers=6, heads=4)
+    Fusion: cross_attention, Task: contrastive
+    '''
+
+    def __init__(self, embed_dim=256, num_layers=6, num_heads=4, num_classes=10):
+        super().__init__()
+        self.embed_dim = embed_dim
+        self.num_layers = num_layers
+        self.num_heads = num_heads
+
+        # image patch embedding
+        self.patch_proj = nn.Conv2d(3, embed_dim, kernel_size=16, stride=16)
+        self.cls_token = nn.Parameter(torch.randn(1, 1, embed_dim) * 0.02)
+        self.pos_embed = nn.Parameter(torch.randn(1, 197, embed_dim) * 0.02)
+        self.dropout = nn.Dropout(0.1)
+
+        # image transformer blocks
+        self.image_blocks = nn.ModuleList([
+            nn.TransformerEncoderLayer(
+                embed_dim, num_heads, embed_dim * 4, 0.1,
+                activation='gelu', batch_first=True, norm_first=True
+            )
+            for _ in range(num_layers)
+        ])
+        self.image_norm = nn.LayerNorm(embed_dim)
+
+        # text embedding
+        self.text_embed = nn.Embedding(30522, embed_dim, padding_idx=0)
+        self.text_pos = nn.Parameter(torch.randn(1, 128, embed_dim) * 0.02)
+        self.text_blocks = nn.ModuleList([
+            nn.TransformerEncoderLayer(
+                embed_dim, num_heads, embed_dim * 4, 0.1,
+                activation='gelu', batch_first=True, norm_first=True
+            )
+            for _ in range(num_layers)
+        ])
+        self.text_norm = nn.LayerNorm(embed_dim)
+
+        # fusion
+        self.fusion_blocks = nn.ModuleList([
+            nn.TransformerEncoderLayer(
+                embed_dim, num_heads, embed_dim * 4, 0.1,
+                activation='gelu', batch_first=True, norm_first=True
+            )
+            for _ in range(2)
+        ])
+        self.fusion_norm = nn.LayerNorm(embed_dim)
+
+        # task head
+        self.classifier = nn.Sequential(
+            nn.Linear(embed_dim, embed_dim),
+            nn.ReLU(),
+            nn.Dropout(0.1),
+            nn.Linear(embed_dim, num_classes),
+        )
+
+        self._initialize_weights()
+
+    def _initialize_weights(self):
+        for m in self.modules():
+            if isinstance(m, nn.Linear):
+                nn.init.orthogonal_(m.weight)
+                if m.bias is not None:
+                    nn.init.zeros_(m.bias)
+            elif isinstance(m, nn.Embedding):
+                nn.init.trunc_normal_(m.weight, std=0.02)
+                if m.padding_idx is not None:
+                    m.weight[m.padding_idx].zero_()
+            elif isinstance(m, nn.LayerNorm):
+                nn.init.ones_(m.weight)
+                nn.init.zeros_(m.bias)
+
+    def encode_image(self, images):
+        x = self.patch_proj(images)
+        x = x.flatten(2).transpose(1, 2)
+        cls = self.cls_token.expand(x.size(0), -1, -1)
+        x = torch.cat([cls, x], dim=1)
+        x = x + self.pos_embed
+        x = self.dropout(x)
+        for block in self.image_blocks:
+            x = block(x)
+        return self.image_norm(x)
+
+    def encode_text(self, input_ids, attention_mask=None):
+        x = self.text_embed(input_ids)
+        x = x + self.text_pos[:, :input_ids.size(1)]
+        x = self.dropout(x)
+        padding = (attention_mask == 0) if attention_mask is not None else None
+        for block in self.text_blocks:
+            x = block(x, src_key_padding_mask=padding)
+        return self.text_norm(x)
+
+    def forward(self, images, input_ids, attention_mask=None, labels=None):
+        image_features = self.encode_image(images)
+        text_features = self.encode_text(input_ids, attention_mask)
+
+        fused = text_features
+        for block in self.fusion_blocks:
+            fused = block(fused)
+        fused = self.fusion_norm(fused[:, 0])
+        logits = self.classifier(fused)
+
+        loss = None
+        if labels is not None:
+            loss = nn.functional.cross_entropy(logits, labels)
+
+        return {'logits': logits, 'loss': loss}
+
+
+if __name__ == '__main__':
+    model = TinyTransformerModel()
+    total = sum(p.numel() for p in model.parameters())
+    print(f'TinyTransformerModel: {total:,} params ({total/1e6:.2f}M)')
+    img = torch.randn(2, 3, 224, 224)
+    ids = torch.randint(0, 30522, (2, 128))
+    mask = torch.ones(2, 128)
+    out = model(img, ids, mask, torch.tensor([0, 1]))
+    print(f'Output: {out["logits"].shape}, Loss: {out["loss"].item():.4f}')