Basic Examples

GUI Examples

Examples of using the simulation core API through a GUI-driven loop.

1) Two-field phase portrait

Create two complex fields, drive them with simple stimuli, and mix them into a phase-portrait view.

local N = 384
local dt = 0.05
local ctx = ooc.create()

ooc.set_timestep(ctx, dt)
ooc.set_visual_mode(ctx, "phase_portrait")
ooc.set_phase_mode(ctx, "scatter")

local carrier = ooc.add_field(ctx, {N}, {
    type = "complex_double",
    fill = {0.0, 0.0}
})

local modulator = ooc.add_field(ctx, {N}, {
    type = "complex_double",
    fill = {0.0, 0.0}
})

ooc.add_zero_field_operator(ctx, carrier)

ooc.add_stimulus_operator(ctx, carrier, {
    type = "stimulus_sine",
    amplitude = 0.6,
    wavenumber = 0.025,
    omega = 0.1
})

ooc.add_stimulus_operator(ctx, carrier, {
    type = "stimulus_sine",
    amplitude = 1.0,
    wavenumber = 0.05,
    omega = -0.2
})

ooc.add_stimulus_operator(ctx, modulator, {
    type = "stimulus_spectral_lines",
    harmonic_count = 1,
    amplitude = 0.22,
    wavenumber = 0.02,
    omega = -0.1
})

ooc.add_mixer_operator(ctx, carrier, modulator, carrier, {
    mode = "multiply",
    lhs_gain = -1.0,
    rhs_gain = 1.0
})

local integrator = ooc.create_context_integrator(ctx, "euler")
ooc.set_integrator(ctx, integrator)

return ctx

2) Gaussian pulse

Applies a moving Gaussian pulse stimulus to a complex field.

local ctx = ooc.create()
local N = 1024

ooc.set_timestep(ctx, 0.02)
ooc.set_visual_mode(ctx, "phase_portrait")

local field = ooc.add_field(ctx, {N}, {
    type = "complex_double",
    fill = {0.0, 0.0}
})

ooc.add_stimulus_operator(ctx, field, {
    type = "stimulus_gaussian_pulse",
    amplitude = 0.25,
    coord_center_x = 0.1,
    sigma_x = 0.15,
    spacing_x = 0.015,
    rotation = math.pi / 3,
    coord_velocity_x = 0.08
})

ooc.add_dispersion_operator(ctx, field, {
    coefficient = 1.6,
    order = 1.2,
    spacing = 0.02
})

local integrator = ooc.create_context_integrator(ctx, "euler")
ooc.set_integrator(ctx, integrator)

return ctx

3) Simple step logger

Attach an observation-only on_step hook that logs time as the context advances.

local ctx = ooc.create()
local dt = 0.01

ooc.set_timestep(ctx, dt)

local field = ooc.add_field(ctx, {64}, {
    type = "real_double",
    fill = 0.0
})

ooc.add_stimulus_operator(ctx, field, {
    type = "stimulus_sine",
    amplitude = 0.1,
    wavenumber = 0.5,
    omega = 0.2,
    scale_by_dt = true
})

local integrator = ooc.create_context_integrator(ctx, "euler", {
    initial_dt = dt
})
ooc.set_integrator(ctx, integrator)

ooc.on_step(ctx, function(c)
    ooc.log("step=%d t=%.3f", ooc.get_step_index(c), ooc.get_time(c))
end)

return ctx

Example output in the log panel:

[INFO] step=1 t=0.010
[INFO] step=2 t=0.020
[INFO] step=3 t=0.030
...

CLI Examples

Examples of using the simulation core API through oakcli.

1) Fixed-step sine stimulus

Applies $A\sin(kx - \omega t)$ to a real field and takes 120 RK4 steps, matching the forced oscillator

$$\dot u(t) = A\sin(kx - \omega t).$$

local ctx = ooc.create()
local steps = 120
local N = 256
local dt = 0.02

ooc.log("Starting simulation with %d steps and dt = %.3f", steps, dt)

local field = ooc.add_field(ctx, {N}, {
    type = "double",
    fill = {0}
})

ooc.add_stimulus_operator(ctx, field, {
    type = "stimulus_sine",
    amplitude = 0.1,
    wavenumber = 1.0,
    omega = 0.2
})

local integrator = ooc.create_context_integrator(ctx, "rk4", {
    initial_dt = dt
})

ooc.set_integrator(ctx, integrator)

for _ = 1, steps do
    ooc.integrator_step(ctx, integrator, dt)
    local values = field:values()
    ooc.log("Field sample value: %.6f", values[1])
end

ooc.shutdown(ctx)

return ctx

Example output:

oakcli run --script fixed-step-sine.lua --steps 0
[INFO] Starting simulation with 120 steps and dt = 0.020
...
[INFO] Field sample value: -0.665682
[INFO] Field sample value: -0.687690
[INFO] Field sample value: -0.710105
[INFO] Field sample value: -0.732928
[INFO] Field sample value: -0.756163
[INFO] Field sample value: -0.779813
[INFO] Field sample value: -0.803878
[INFO] Field sample value: -0.828362
...