Basic Examples

GUI Examples

Examples of using the simulation core API via the graphical user interface (gui).

1) Kepler orbits in phase portrait mode

Generate Kepler style orbits in phase portrait mode.

local N = 512
local dt = 0.05
local ctx = ooc.create()

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

local field_1 = ooc.add_field(ctx, {N}, {
    type = "complex_double",
    fill = {0.0, 0.0}
})

local field_2 = ooc.add_field(ctx, {N}, {
    type = "complex_double",
    fill = {0.0, 0.0}
})

ooc.add_stimulus_operator(ctx, field_1, {
    type = "stimulus_sine",
    amplitude = 0.25,
    wavenumber = 0.025,
    omega = -0.3,
    phase = 0
})

ooc.add_stimulus_operator(ctx, field_1, {
    type = "stimulus_sine",
    amplitude = 0.25,
    wavenumber = 0.05,
    omega = -0.3,
    phase = math.pi/2,
    rotation = math.pi/4,
})

ooc.add_stimulus_operator(ctx, field_2, {
    type = "stimulus_spectral_lines",
    amplitude = 0.25,
    wavenumber = 0.03,
    omega = -0.2,
    phase = 0
})

ooc.add_mixer_operator(ctx, field_2, field_1, field_1, {
    mode = "multiply",
    lhs_gain = 0.5,
    rhs_gain = 0.5
})

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 real field.

local N = 768
local dt = 0.025

local ctx = ooc.create()

ooc.set_timestep(ctx, dt)
ooc.set_visual_mode(ctx, "polar")

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

ooc.add_zero_field_operator(ctx, field)

ooc.add_stimulus_operator(ctx, field, {
    type = "stimulus_gaussian_pulse",
    amplitude = 0.25,
    sigma_x = 0.75,
    velocity_x = 1,
    coord_center_x = math.pi
})

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

ooc.set_integrator(ctx, integrator)

return ctx

3) Simple log hook

local N = 512
local dt = 0.01
local ctx = ooc.create()

ooc.set_timestep(ctx, dt)
ooc.on_step(ctx, function(c)
    local t = ooc.get_time(c)
    ooc.log("t=%.3f", t)
end)

return ctx

Example output in log panel:

[INFO] t=0.000
[INFO] t=0.010
[INFO] t=0.020
[INFO] t=0.030
...

CLI Examples

Examples of using the simulation core API via the command-line interface (cli).

1) Fixed-step sine stimulus

Applies $A\sin(kx - \omega t)$ to a real field and takes 120 integrator (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:

oak@field % ./bin/cli --script fixed-step-sine.lua
[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
...