NEWS.md
Fixed catastrophic hash collisions in FreqTable::make_hash and vecHasher: hashes of small-integer statistics had no entropy in their low bits, so std::unordered_map placed (nearly) all keys in a single bucket, making support computation O(4^ncol) instead of O(2^ncol). Models with many response columns (e.g., 16) appeared to hang during initialization (USCbiostats/barry#24).
FreqTable::add() now verifies the stored row on a hash hit and keeps true 64-bit hash collisions in a per-hash overflow chain, so distinct statistics can no longer be silently merged (USCbiostats/barry#24).