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RoPE in Transformer Self-Attention
2025/06/29·StepFun can make mistakes, check important info.
does RoPE apply to all query, key and value?

Yes, RoPE (Rotary Position Embedding) is applied to all query, key, and value vectors in the self-attention mechanism of a transformer model.

How RoPE Works:

  1. Positional Encoding: Unlike traditional positional encodings (such as sinusoidal encodings), RoPE encodes positional information by rotating the query, key, and value vectors based on their positions in the sequence.

  2. Rotation Matrix: RoPE uses a rotation matrix that depends on the position index. This matrix is applied to the query, key, and value vectors before they are used in the self-attention computation.

  3. Complex Number Representation: RoPE can be viewed as treating the vectors as complex numbers and rotating them in a complex plane. The rotation angle is proportional to the position index.

  4. Relative Positional Information: By rotating the vectors based on their positions, RoPE injects relative positional information into the self-attention mechanism. This allows the model to capture dependencies between tokens based on their relative positions, rather than just their absolute positions.

Application to Query, Key, and Value:

  • Query Vector (Q): RoPE is applied to the query vector for each token in the sequence. This ensures that the query vector captures the positional information of the token it represents.

  • Key Vector (K): Similarly, RoPE is applied to the key vector for each token. This allows the model to compare the query vector with the key vectors based on their relative positions.

  • Value Vector (V): RoPE is also applied to the value vector for each token. This ensures that the value vector captures the positional information of the token it represents, which is important for the final output of the self-attention mechanism.

Benefits of RoPE:

  • Relative Positional Awareness: RoPE enables the model to capture dependencies between tokens based on their relative positions, which is crucial for understanding the structure of natural language.

  • Generalization to Longer Sequences: Since RoPE encodes relative positional information, it allows the model to generalize better to longer sequences than traditional positional encodings.

  • Improved Performance: Empirical studies have shown that RoPE can improve the performance of transformer models on various natural language processing tasks.

In summary, RoPE is a powerful positional encoding method that is applied to all query, key, and value vectors in the self-attention mechanism of a transformer model. It allows the model to capture relative positional information and improves its ability to understand and process natural language.