pytc.df.pivots

Streaming exact-column pivot selection for molecular ISDF.

The selector in this module deliberately owns no dense grid-by-grid matrix. It consumes an exact metric diagonal and a callable that evaluates requested columns. Molecular ISDF backs that interface with already-resident weighted orbital factors; periodic ISDF has a separate implementation and a streamed AO provider, but uses the same batch controls and schedule.

Functions

_blocked_round
_diverse_local_pivots	Select an exact greedy subset from a stale-diagonal candidate pool.
_sequential_round
grad_columns	Exact requested columns of the weighted density-gradient metric.
grad_diagonal	Diagonal of the weighted molecular density-gradient metric.
phi_columns	Exact requested columns of the weighted molecular density metric.
phi_diagonal	Diagonal of K_rs = (phi[:, r]^T phi[:, s])**2.
pivoted_cholesky_streaming	Select pivots from an exact diagonal and exact batched-column oracle.
validate_pivot_controls