traj.jsonl contains one JSON object per sampled frame, one object
per line. The viewer skips blank and malformed lines. All quantities use reduced
units with kB = m = 1 in two dimensions.
| Key | Type | Meaning |
|---|---|---|
step | integer | Production step index |
t | float | Production time, step × dt |
pos | array of [x, y] | One wrapped position per atom |
vel | array of [vx, vy] | One velocity per atom |
E_pot | float | Total shifted Lennard-Jones potential energy |
E_kin | float | Total kinetic energy |
Optional run.json supplies n, rho,
box as [Lx, Ly], dt, temperature, and
ramp_to for heating runs. The box fixes the periodic geometry;
without it the viewer estimates dimensions from position extents. Temperature
and ramp_to define the target temperature history.
Locally, drop traj.jsonl and its run.json onto this
page, or use choose file(s)…. To add metadata afterwards,
use load run.json…. A new trajectory replaces the previous
run metadata.
To share a committed recording, open this course page with
?src= followed by the raw GitHub URL of traj.jsonl.
The viewer looks for run.json beside it. Press
save PNG or s to save a frame with its readouts.
Space toggles playback; the arrow keys step through frames.
The md command contract specifies the simulator interface. The physics gate contract specifies the complete required metadata, sample chronology, and checks. See also the viewer guide.