board.track_width
a copper track's width on a net (metres, shown in mm)
What it is ¶
board.track_width(net, mm) yields one row per net that has routed copper, giving the net’s
MINIMUM track width, held in metres and shown in mm. net is the net name (the join key to
ir.Net.name); mm is a number, so a query compares it with a unit (?w < 0.2mm). A net routed
with several widths reports only its thinnest segment, not every segment.
For hardware engineers ¶
The narrowest copper on a net sets its worst-case current-carrying capacity, so a review cares about that number. A power or ground net that necks down to a thin trace somewhere is a current-density risk even if most of its copper is wide. Query this to find nets routed below a width floor, or to sanity-check that a high-current rail never drops under its intended minimum. The value is the physical track width, so you compare it against a real length, written with its unit.
For software engineers ¶
The routed net is a set of track segments, each with a width. board.track_width is an aggregate
projection over that set, reducing it to the minimum width keyed by net. The minimum is the
safety-relevant extreme. Reporting it instead of one row per raw segment gives a compact per-net
answer rather than a full segment dump. Rows are 1:1 with nets that have at least one track; a net
with pads or vias but no routed track contributes no row. The stored unit is nanometres. The
projector converts to metres, since the engine folds a query literal to that SI base, and a
cell is shown in millimetres.
Go projector ¶
boardFacts in stdlib/relations/facts.go walks Model.BoardNets() and calls the helper
minSegmentWidthNm(bn.Segments) for each net. The helper returns the smallest Width across the
net’s track segments. It returns a false ok when the net has no segments, and then no row is
emitted. The
nanometre minimum is converted with nmToMM, shown as millimetres, and emitted as
board.track_width(net, mm) with the numeric value populated in metres for comparison.
The board tier is EMPTY on a netlist-only design. Model.BoardNets() returns nothing unless the
design was loaded with board geometry (check.WithBoard, fed a .kicad_pcb or IPC-2581 board
sidecar). A query sees no error in that case. board.track_width yields zero rows on any design
without board geometry, as the datasheet tier does without --params. So a query returning nothing
does not mean every track is wide. It can mean the design carries no board at all.
Datalog ¶
Every net and its minimum track width:
board.track_width(?n, ?w) => ?n, ?w
Nets whose thinnest track drops below 0.2 mm:
board.track_width(?n, ?w), ?w < 0.2mm => ?n, ?w
Write the threshold with its unit. A width is held in metres and shown in millimetres, so a bare
0.2 would mean 0.2 m and every net would answer.
Both need a board-bearing design (a .kicad_pcb or an IPC-2581 file); on a netlist-only load they
return nothing.
Schematic ¶
