serversdown/seismo-relay
1
0
Fork 0
Code Issues 6 Pull Requests Actions Packages Projects Releases 1 Wiki Activity

docs: sharpen the series-3 histogram open item — dropped intervals, not wrong values

Browse Source 
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
This commit is contained in:
serversdown
2026-08-25 16:23:51 +00:00
co-authored by Claude Opus 5
parent 4f8224a751
commit e449ac04af
2 changed files with 14 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
CLAUDE.md
+13 -6
View File
@@ -276,12 +276,19 @@ Corpus result, end to end through the production path:
anchor count — `01 00` records appear with both 2- and 4-byte anchor
fields in the same file. Examples: `BE12599/N599LPNB.JF0W` @1155,
`BE12599/N599LPWJ.980W` @849, `BE9558/K558LOF2.820W` @1485.
- **Histogram codec misses the peak interval** — 301 of 1141 series-3
histogram channels (26%) decode a peak below 95% of the
device-reported PPV (one reads 0.0300 against a device PPV of 0.1200,
exactly 1/4). Not a scale error — that would be a uniform 2.34%.
Lives in `histogram_codec.decode_histogram_body`, untouched by the
2026-08-25 waveform pass.
- **Histogram codec drops trailing intervals (series-3)** — the
per-interval *values* are right: measured against the histogram ASCII
data table (Tran/Vert/Long peak + freq + PVS per interval), 1031 of
1196 files (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). When a dropped interval holds the event peak, the decoded max
falls below the device-reported PPV: 169/1196 files (14%). A
termination bug in `histogram_codec.decode_histogram_body` — same
family as the waveform-walker truncation fixed 2026-08-25, and
untouched by it. Note: the histogram ASCII carries a full
per-interval table, so this has proper ground truth available (1211
files in the prod snapshot).
- **Micromate (UM-series) IDF decode is ~1000× low** — e.g.
`UM11402_20260406130113.IDFW` gives a Tran peak of 0.0009 in/s against
a device-reported 1.1168. The Thor IDF path decodes sanely, so this