Advanced Examples

CLI Examples

Examples of more advanced Lua usage patterns, including on-step hooks, custom operators, async logging, and multi-field coupling.

1) Parameter Sweep with On-Step Hook

Sweeps wavenumber on operator index $1$ as $k(t) = \sin(5\times10^{-4} t)$

-- stimulus_sine_184#0 (schema=stimulus_sine, index=1)
sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_sine",
    amplitude = 0.4,
    wavenumber = 1,
    omega = -0.4,
    spacing = 1
})

local t = 0

sim.sim_on_step(ctx, function(c)
    t = t + 1
    local sweep = math.sin(t * 0.0005)
    sim.sim_operator_param_set(c, 1, "wavenumber", sweep)
end)

2) Lua-defined Operator

Defines a custom operator in Lua that counts simulation ticks and logs step metrics every 1000 steps.

local tick = 0
local tick_op = sim.sim_add_operator(ctx, 'tick_counter', function(context)
    tick = tick + 1

    if tick % 1000 == 0 then
        local metrics = sim.sim_step_metrics_latest(ctx)
        if metrics then
            sim.log("Step %d: dt=%.6f, writes=%d", tick,
                metrics.accepted_dt, metrics.dirty_writes)
        end

    end
    return true
end)