fix(tdigest): preserve stored min and max when merging - #280
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jaideeppyne wants to merge 1 commit into
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jaideeppyne wants to merge 1 commit into
jaideeppyne wants to merge 1 commit into
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Merging a digest whose extreme centroids have weight greater than one re-derived min and max from those centroid means. Copy the stored extrema from the other digest first so rank and quantile tail interpolation stay correct, especially for deserialized reference-format images. Fixes apache#277.
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Fixes #277.
Summary
min/maxfrom the other digest inTDigestMut::mergebefore compressing the combined centroid list.Why
Compression never merges the extreme centroids for digests built through
update, so this is invisible on that path. Reference-format and other deserialized images can store min/max strictly outside the extreme centroid means.mergepreviously ignored those fields and re-derived extrema from centroid means, so:min_value()/max_value()drifted inwardThis is the same class of tail-interpolation defect as #250, on the merge path rather than the query formulas.
Validation
cargo test -p tests-integration --test tdigest_testcargo +nightly clippy -p datasketches --all-features -- -D warnings