One op, not two: a running median followed by a one-pole at `fc`. The median kills an impulse
outright -- a peak shorter than half its window cannot move it at all -- and the pole then
takes the broadband hash the median leaves behind. Chaining the existing `LowPass` after a
median would let the user wire them the wrong way round, and a pole *before* a median feeds
the impulse into the filter's state for its whole settling time, which is the thing the node
exists to avoid.
`DeNoise` is **appended** at `math_op_at(12)` (with `Div` given its explicit `case 11`, so the
`default` no longer swallows it): a session stores an op as its index through that accessor,
so inserting it beside the filters in the dropdown would reinterpret every node in every
existing session file. It sits last in the dropdown instead, which is the right side of that
trade.
The median window is `MathNode::med_n`, odd and 3..9, enforced by `median_n()` rather than by
the dialog -- a file holding anything else still loads -- and the ring is *pooled* in
`MathRuntime::median`, sized in `math_prepare()`, because nine doubles as a member would push
`MathNodeRt` across two cache lines for every node, filter or not. The pole reuses `b0`/`z1`,
which `math_prepare()` already carries across a re-prepare, so a decimation change does not
make its trace jump.
Warm-up takes the median of what the window holds rather than NaN: in this application NaN
means *a hole in the data*, and spending that meaning on a start-up transient would make a gap
ambiguous. A non-finite input stays a hole and leaves both the window and the pole alone.
\`add node\` made a gain and nothing else, so every other op was two steps. It
is a menu of the twelve now, each carrying its index through
\`math_op_index()\`'s space rather than a cast of the enum -- which is also
what \`math_dialog_sync()\` now uses to drive the op dropdown, since that
order is the dialog's and not the declaration's.
The evaluator walks the node list in order, which used to make the order the
user's problem -- an input of an earlier node was not even drawn as
connectable. `math_connect()` runs Kahn's algorithm over the trial edge set,
with ties broken by the current index so a graph already in order is not
permuted, and remaps every index the dialog holds in one block. A self wire
and a cycle are refused with a message and change nothing.
The flicker ("no data" at no constant frequency, worse with the measurements
and cursors panes up) was a torn read of the window's first stamp: acquire()
pins the window to the ring's oldest slot, and reading it at paint time races
the producer lapping it, returning a stamp one ring span too new. x0() is the
origin every trace point is reconstructed from, so one torn read produced a
refused neighbours(), a filter that dropped three quarters of the points, and
a polyline shifted off its axis. It is cached by acquire() under the lock now.
EventSeries::neighbours() answered from the (x - x0)/dx grid, whose drift from
the real arrival stamps arrives as a constant offset in seconds -- a doubling
share of the screen per zoom step, which is the "zooming into a held event
clips it more from the left" report. Both series binary-search the stamps now.
The measurements pane went through the LOD pyramid rather than reading its
window raw (19.7 ms per recompute to 1.2 ms, 0.1% of a 2 M-sample window) and
recomputes on a cadence; the math engine lost a per-slot heap allocation, a
per-sample source lookup by name and a fetch_add that cost more than the
arithmetic it counted.
The cursors pane's mix mode drew a line per *named* slot, so a slot holding a
signal that can never produce a channel -- the stream's timestamp -- got a row
that could only read "--", and such names were re-saved every session. It
counts bound traces now and apply_layout() refuses them.
Four toolbar icons are drawn for this app and compiled in as a GResource: the
stock ones were a record dot for the trigger and three magnifiers for cursors,
measurements and math.
New probes and dump lines for all of it (trace ink, measure cost, math cost,
event zoom, toolbar icons); README and CLAUDE.md record what they cure.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Martino Ferrari