anti
66c73ce59d
Per-session 64-bit SimHash of inter-keystroke digraph flight times: walk single-char input events, accumulate flight time per (c1,c2), bucket the median, Charikar-SimHash the bucketed pairs. Locality- sensitive so the same typist is Hamming-close across sessions; pastes and think-pauses break the chain; silent below the sample-size floor. New shared decnet/util/simhash.py (simhash64/hamming64/bytes helpers). Registered as a conditional Tier-A primitive (count 37->38); requires behave-shell>=0.1.2.
39 lines
1.3 KiB
Python
39 lines
1.3 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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"""Charikar SimHash util — determinism, LSH property, byte round-trip."""
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from __future__ import annotations
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from decnet.util.simhash import from_bytes8, hamming64, simhash64, to_bytes8
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def test_empty_or_zero_weight_is_zero() -> None:
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assert simhash64({}) == 0
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assert simhash64({"a": 0, "b": -3}) == 0 # non-positive weights skipped
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def test_deterministic() -> None:
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tokens = {"th": 3, "he": 2, "er": 1}
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assert simhash64(tokens) == simhash64(dict(tokens))
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def test_near_duplicate_low_hamming() -> None:
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base = {f"dg{i}": (i % 5) + 1 for i in range(40)}
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identical = dict(base)
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perturbed = dict(base)
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perturbed["NEW_PAIR"] = 1 # one extra low-weight token
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assert hamming64(simhash64(base), simhash64(identical)) == 0
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assert hamming64(simhash64(base), simhash64(perturbed)) <= 8
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def test_disjoint_high_hamming() -> None:
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a = {f"a{i}": 2 for i in range(30)}
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b = {f"b{i}": 2 for i in range(30)}
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# Unrelated token sets ≈ half the 64 bits differ; comfortably ≥ 20.
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assert hamming64(simhash64(a), simhash64(b)) >= 20
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def test_bytes_roundtrip_is_8_bytes() -> None:
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h = simhash64({"x": 1, "y": 2, "z": 5})
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raw = to_bytes8(h)
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assert isinstance(raw, bytes) and len(raw) == 8
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assert from_bytes8(raw) == h
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