Comprehensive Guide to Transformer: Attention is All We Need

Step 1: Input Processing

The Transformer begins with constructing a dataset, extracting words, and building a vocabulary. Each word is assigned a unique index, simplifying the tokenization process.

Step 2: Input Embedding

Words are mapped into dense numerical representations. These embeddings capture syntactic and semantic properties of words and provide an effective input for the model.

Step 3: Positional Encoding

Since Transformers do not have recurrence, positional encodings are added to input embeddings to retain word order information.

Step 4: Multi-Head Attention Mechanism

Multi-head attention enables the model to focus on different parts of the sequence simultaneously, learning contextual relationships between words.

Step 5: Residual Connections and Normalization

Skip connections (residual connections) help gradient flow, reducing vanishing gradient problems, while layer normalization stabilizes learning.

Step 6: Feed-Forward Network

Each position in the sequence independently undergoes two dense layers with a non-linear activation function, enhancing the model's expressiveness.

Step 7: Additional Normalization

Layer normalization is applied again to prevent unstable updates and optimize training.

Step 8: Decoder’s Input Processing

Similar to the encoder, the decoder processes input embeddings with positional encoding.

Step 9: Masked Multi-Head Attention

The decoder employs masked attention, ensuring that predictions for each word only depend on previously generated words.

Step 10: Output Generation

The final linear layer maps the decoder output to a probability distribution over the vocabulary using softmax.

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