methods / Causal Validation / Singular-direction decomposition and pruning of transformer components
Singular-direction decomposition and pruning of transformer components
Takes the SVD of a transformer component's augmented weight matrix (e.g. an attention head's OV/QK circuit) to decompose it into orthogonal singular directions, then learns a diagonal mask that prunes most directions while measuring how much task accuracy/behavior survives — turning "one head, one function" into "one head, several functions living in distinct orthogonal directions of its own weight space."