Re-measured properly. The first pass compared h5 max against the ASCII
header PPV and reported "26% of channels miss the peak". The histogram
ASCII actually carries a full per-interval data table (Tran/Vert/Long
peak + freq + PVS per interval), which is real ground truth, so the
comparison should have been per-interval from the start.
Per-interval result, n=1196 series-3 histograms:
- decoded VALUES are right: 1031/1196 (86%) match within 1 LSB across
the overlapping prefix
- the interval COUNT is short in 1195 of 1196 files: median 1 missing,
1088 short by 1-2, 65 by 3-10, 39 by 11-100, 3 by >100 (max 205)
- decoded max falls below the device PPV in 169/1196 files (14%), not
26% — that happens when a dropped interval held the peak
So it is a termination bug in histogram_codec.decode_histogram_body,
the same family as the waveform-walker truncation fixed earlier today,
rather than mis-decoded interval values. Series-3 only; there is no
preserved series-4 ASCII in the snapshot to compare against.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog
serversdownandClaude Opus 5
e449ac04af