Three defects, all of them a window describing data that is not there.
A math edit refilled the derived ring with `clear()`, which renumbers it
from 0, leaving `produced()` short by the inputs' retained base. Since
`live_window_locked()` clamps against every channel's `produced()`, that
one lagging channel answered `n = 0` for the live view, every pause view
and every trigger capture until a whole ring of fresh data had gone by --
the reported freeze, invisible until the ring first wraps, hence its
intermittence. It now restarts with `clear_to(base)`, and
`ChannelBuffer::republish_from(base)` puts the published window back:
`acquire()` is incremental, so a rewrite in place published nothing and
the pyramid went on describing the samples the edit replaced.
The trigger's channel is an index, re-resolved by name after a renumbering
-- but only in `rebuild_enabled_locked()`, so a math add or delete went
through `set_math_channels()` with no restore, the index was clamped to
-1, and `process()` returned at once while the panel still named the
channel. The restore moves into `rebuild_channels()`, which *is* the
renumbering, so no caller can forget it.
And `update_measures()` suppressed its "the window moved" test while an
event was held -- the one mode where a gesture is the only thing that can
move it. Zooming a latched event left the pane describing the whole
captured event. A pinned window needs no exemption: it lands on the range
it already measured and fails the 2 % test by itself.
The checks that missed all three: `UDPSCOPE_PROBE_MATHWRAP_MS` edits a
graph whose ring has already wrapped, which `math_probe` structurally
cannot reach; `[measure-trace]` now prints the mode, the window on screen
and the window the numbers describe; and the dump's `marks_in_window`
counts against the window on screen instead of against the one the marks
were computed over, where it was a tautology.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
`top`, `bottom` and `amplitude` became the *flat levels* in e83ad86 -- the level the
signal dwells at, read from the density of the window's buckets -- and that change kept
the split's own two means as its internal fallback for a window the pyramid cannot
summarize. Those means are now three types of their own, so the two different questions
about one split can be asked side by side: `above %` and `below %` are the plain mean of
the samples on one side of a share -- the reading the old `top`/`bottom` gave -- and
`between % %` is the mean of the band between two shares, which no single split can
answer, because a band's two edges are two thresholds.
Nothing about the arithmetic is new, and nothing is a new pass. `Above`/`Below` are the
`sum[]`/`count[]` split `measure_accumulate()` already folds -- the very figures
`Top`/`Bottom` fall back to -- and `Between` is the **difference of two levels' upper
sides**, both of which come out of one pass two over one window. It rides the bucket
fast path unchanged: a bucket wholly inside the band is strictly above the lower level
and strictly below the upper one, so both accumulators fold it whole, and only the
buckets that straddle either edge are opened. `measure_level_pcts()` is the one place the
shares are read, and it clamps both and puts `between`'s pair **in order**, so "between
80 % and 20 %" is the band between 20 % and 80 % -- normalized rather than refused,
because the shares name two edges rather than a direction. Nothing to measure reads `--`,
as for every other type: a share at 100 % has no sample above it, and a band can hold
none at all.
Measured, `[bandavg-probe]`, fast mock at a 2 s window (`--rate 1300000 --batch 1000
--freq 1`):
sine `above 50` 0.636620 (2/pi), `below 50` -0.636620, `between 50 75` 0.255873
square `above 50` 0.986496 (30 harmonics) / 1.000000 (--square-harmonics 0),
`between 50 75` 0.302744 / --
ramp `between 50 75` 0.250000 and `above 50` 0.500000, `above 100` --
The first three are the figures the old `top`/`bottom` documented; the ramp's are what a
uniform density predicts (a band's mean is its own centre); the ideal square's empty band
is the nothing-to-measure rule. The pane offers the types and edits their percentages
through the dialog's second share -- which only `between` shows -- and a measurement's
pair survives add/edit/delete and the session file (`threshold2`), where a file written
before it existed loads at the default.
No raw pass: with the measurements probe adding one of every type at a 2 s window, `raw`
went from 113966 of 240719031 covered (0.0%) to 134978 of 255372033 (0.1%), 0.8 -> 1.1
ns a covered sample.
Docs: the band-average invariant (and the two assertions the flat-level change moved),
the probe readings for the new probe, the verification recipe, the manual's measurements
page and the README.
A bench scope separates Vtop/Vbase from Vmax/Vmin because a band-limited
edge overshoots and rings: the mock's `square` at 30 harmonics reaches
±1.179 where its plateau is ±1. On the rippled square the old readings were
a property of the edges rather than of the waveform -- `top` 0.986496,
`amplitude` 1.179350 -- and `amplitude` reported the overshoot.
`top`, `bottom` and `amplitude` are now the flat levels and their delta.
A flat level is a density question -- the plateau holds most of the
samples and the ringing a few percent -- so `measure_scan_buckets()` folds
a 64-bin histogram of the whole buckets' midpoints while it has the list in
hand (one observation per bucket, each bin carrying its buckets' exact sum
and finite count), and `measure_flat_levels()` takes, either side of the
split, the densest bin holding at least half the densest one's buckets --
the outermost of those, which is what makes a waveform with no plateau read
its peak -- and the exact mean of the samples of the buckets within 5 % of
the window's peak-to-peak of it. 5 % is deliberately under the ~9 %-of-swing
Gibbs overshoot. `amplitude` is `top - bottom` (a scope's Vamplitude), not
the half-swing it was.
Measured, fast mock, 2 s window, harmonics 0 -> 30: top 1.000000 ->
0.999983, bottom -1.000000 -> -0.999983, amplitude 2.000000 -> 1.999966,
while `peak to peak` keeps the extremes (2.000000 -> 2.358701). On the 1 Hz
sine top is 0.957988 (it was 0.636620, the half-wave mean; a sine has no
plateau, so the densest band is at its peak) with sd 0.0014 over a scrolling
window, and `peak to peak` is still exactly 2.
No raw pass and no new fetch: the histogram is the same fetched bucket list
read a second time, gated on a pane that holds one of the three types.
`raw` is unchanged (0.1% clean, 2.1% with the --noise 0.1 interferer,
against 0.1%/2.1% before) for 0.44 -> 0.50 ms and 0.52 -> 0.65 ms a pass.
A window the pyramid cannot summarize -- an hf-filtered walk, or one shorter
than a bucket -- keeps the old readings: the mean of each side of the split,
and the window's peak to peak for amplitude.
Docs: the flat-level invariant (and the two 2/pi assertions it replaces),
the probe readings, the manual's measurements page and the README.
README gains the three controls where each lives -- the trigger's `band`/`reject`, the
measurement's `noise`/`hf`, and the math channel's `de-noise` node -- each with its unit, what
"off" is, and what it costs, plus the two deliberate deviations from the design spec next to the
features they belong to: the band applies to `edge` and `window` only (a pulse's width is measured
from a crossing to its return, so a band there changes the measured width rather than rejecting
noise; a dropout is an absence with no level to compare), and the band is verified through
`BufferSearch` hit counts rather than `[condition-probe]` latch times, because probe-readings.md
states that a `t0` is not an assertion.
The invariant docs gain the rules a later change must not break: `EventCondition`'s two new fields
and the once-per-packet `configure(dt)` that must not reset; the crossing rule that a change is
between two *decided* sides; the measurement path's exception to "a readout quotes a stored
sample", why the band moves the edge decision only, why `measure_accumulate` loops samples outer,
and why a filtered window disables both bucket fast paths; that `MathOp` is append-only (the index
*is* the serialisation), that the median window is pooled in the runtime rather than held per node,
why the pole reuses `b0`/`z1`, and that median-then-pole is the design; the session's named
`noise`/`hf` keys and its thirteen-field node string that still reads twelve; and the two GTK
traps -- positionally brace-initialised dialogs, and a control that cannot apply being hidden
rather than disabled.
The file was 1967 lines and is auto-loaded into every context, so every
session paid for the whole of it to reach one invariant. It now carries the
project's goal, the three facts that are always relevant, and a table of
contents; the body is fourteen files under docs/claude/ reached by link
rather than by import, so nothing is loaded until it is asked for.
The content is moved verbatim -- the only edits are each file's own header
and the cross-references that became cross-file ("see the invariant below"
is now a link to the file that owns it).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
