Transformer Architecture Explained
Overview The Transformer architecture, introduced in “Attention Is All You Need” (2017), revolutionized NLP and now powers all modern LLMs. Key Components Input → Embedding → Positional Encoding → Transformer Blocks → Output ↓ [Multi-Head Attention + FFN] × N Self-Attention The core mechanism that allows tokens to attend to all other tokens. import torch import torch.nn.functional as F def attention(Q, K, V, mask=None): d_k = Q.size(-1) scores = torch.matmul(Q, K.transpose(-2, -1)) / (d_k ** 0.5) if mask is not None: scores = scores.masked_fill(mask == 0, -1e9) weights = F.softmax(scores, dim=-1) return torch.matmul(weights, V) Multi-Head Attention Run attention in parallel with different learned projections: ...