8409c852ef1cb686db08092a6aea6665243e9148
Introduces parallel `count_ones` for `BitMatrix` and parallel column-sum aggregation alongside three pairwise distance constructors (Bray-Curtis, Euclidean, Hellinger) for `IntMatrix`. These methods support partial, layer-wise data by accepting precomputed global column sums for normalization, enabling additive decomposition across partitions. Includes unit tests verifying mathematical equivalence and partition additivity.
Description