Potential & Stimulus Operators

All stimulus operators take a destination field and an options table; most support scale_by_dt (bool) to scale writes by the simulation timestep.

〰️ Sine

sim_add_stimulus_operator(ctx, field, opts)

Travelling sinusoid.

• type (required): "stimulus_sine".
• amplitude (required): peak amplitude.
• wavenumber (required): spatial wavenumber.
• omega (required): angular frequency.
• phase: phase offset.
• origin, spacing: map index to coordinates.
• time_offset: temporal shift.
• nominal_dt, fixed_clock: lock timing when desired.
• velocity: propagation speed.
• rotation: complex phase rotation on output.
• scale_by_dt: scale writes by dt.

Example:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_sine",
    amplitude = 0.3,
    wavenumber = 1.0,
    omega = 0.6,
    velocity = 0.2
})

🌊 Standing Wave

sim_add_stimulus_operator(ctx, field, opts)

Standing-wave sinusoid (velocity defaults to 0).

• type (required): "stimulus_standing".
• Same parameters as stimulus_sine (amplitude, wavenumber, omega, phase, origin, spacing, time_offset, nominal_dt/fixed_clock, rotation).
• Velocity typically 0; use phase to set node/antinode placement.

Example:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_standing",
    amplitude = 0.4,
    wavenumber = 0.8,
    omega = 0.8,
    phase = 0.25
})

🐦 Chirp

sim_add_stimulus_operator(ctx, field, opts)

Sinusoid with time-varying frequency/wavenumber.

• type (required): "stimulus_chirp".
• amplitude, wavenumber, omega, phase, origin, spacing.
• kdot (wavenumber rate), wdot (frequency rate) for chirp.
• velocity, rotation, time_offset.
• nominal_dt, fixed_clock, scale_by_dt.

Example:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_chirp",
    amplitude = 0.5,
    wavenumber = 1.0,
    omega = 0.3,
    kdot = 0.1,
    wdot = 0.2
})

💨 Travelling Gaussian Envelope

sim_add_stimulus_operator(ctx, field, opts)

Travelling sinusoid with Gaussian envelope.

• type (required): "stimulus_gaussian_travel".
• amplitude, wavenumber, omega, phase, origin, spacing.
• Envelope: gaussian_center, gaussian_sigma (set >0 to enable).
• velocity, rotation, time_offset.
• nominal_dt, fixed_clock, scale_by_dt.

Example:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_gaussian_travel",
    amplitude = 0.6,
    wavenumber = 1.0,
    omega = 0.5,
    gaussian_sigma = 18.0,
    gaussian_center = 0.0,
    velocity = -0.3
})

💥 Gaussian Pulse

sim_add_stimulus_operator(ctx, field, opts)

Pure Gaussian envelope (no carrier).

• type (required): "stimulus_gaussian".
• amplitude (required): peak amplitude.
• center (default 0): envelope center coordinate.
• sigma (required): width of Gaussian.
• velocity (default 0): center propagation speed.
• origin, spacing: index-to-coordinate mapping.
• time_offset (optional), rotation (complex phase), nominal_dt, scale_by_dt.

Examples:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_gaussian",
    center = 128,
    sigma = 30,
    amplitude = 1.0
})

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_gaussian",
    center = 0,
    sigma = 10,
    amplitude = 0.5
})

🌈 Spectral Lines

sim_add_stimulus_operator(ctx, field, opts)

Harmonic spikes in frequency.

• type (required): "stimulus_spectral_lines".
• amplitude (required): peak amplitude.
• wavenumber, omega, phase: base line parameters.
• harmonic_count (≥1): number of lines.
• harmonic_power (≥0): power weighting across harmonics.
• fixed_clock (bool), nominal_dt (optional), scale_by_dt.

Examples:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_spectral_lines",
    amplitude = 1.0,
    wavenumber = 0.5,
    harmonic_count = 1
})

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_spectral_lines",
    amplitude = 0.2,
    harmonic_count = 4,
    harmonic_power = 0.9,
    fixed_clock = true
})

🏁 Checkerboard

sim_add_stimulus_operator(ctx, field, opts)

Checker/stripe pattern; works on complex fields.

• type (required): "stimulus_checkerboard".
• amplitude (required): pattern amplitude.
• period_x, period_y: periods along each axis.
• checker_phase: scalar phase offset.
• checker_complex_phase: complex rotation applied to pattern.
• scale_by_dt: scale writes by dt.

Examples:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_checkerboard",
    amplitude = 1.0,
    period_x = 8,
    period_y = 8
})

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_checkerboard",
    amplitude = 0.5,
    period_x = 12,
    period_y = 6,
    checker_complex_phase = 0.75
})

📦 Gabor Kernel

sim_add_stimulus_operator(ctx, field, opts)

Gaussian-windowed sinusoid.

• type (required): "stimulus_gabor".
• amplitude (required): peak amplitude.
• wavenumber, omega, phase: carrier controls.
• center, sigma (required): Gaussian window location/width.
• origin, spacing: coordinate mapping.
• velocity, rotation, time_offset.
• nominal_dt, fixed_clock, scale_by_dt.

Examples:

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_gabor",
    amplitude = 0.4,
    sigma = 12.0,
    wavenumber = 0.5
})

sim.sim_add_stimulus_operator(ctx, field, {
    type = "stimulus_gabor",
    amplitude = 0.2,
    omega = 0.5,
    rotation = 0.3,
    center = 64,
    sigma = 20
})