RoPE Position Interpolation Compresses Indices Before Rotation
Rotary position embeddings apply a position-dependent rotation to query and key components before their dot product is evaluated. If a model was trained with positions up to a reference length, simply sending much larger position indices into the same rotation rule can place attention in angular regimes that were not represented in that training range. Position interpolation changes the coordinate supplied to RoPE. For an extension factor s > 1, a simplified form maps