Pamoja.Sim 0.2.0

Pamoja.Sim

Noisy and replay sensors, a recording actuator, a simulated robot that dead-reckons its pose, and a link that loses sends on a pattern. One capability of pamoja, one memory-safe Rust core with bindings for TypeScript, Python, and C#.

Install

dotnet add package Pamoja.Sim

using Pamoja.Sim;

This pulls in Pamoja.Native, the compiled engine, and Pamoja.Codec and Pamoja.Kit. dotnet add package Pamoja is the whole framework in one package.

Example

The guide project's example, spliced here as it ran in CI.

From bindings/dotnet/samples/Pamoja.Guides/SimGuide.cs:

// The clear distance ahead, in meters, replayed from an earlier survey of the
// row, so every run sees the same row.
using var ahead = new Replay([4.0f, 3.0f, 1.5f, 0.5f]);
// The drive keeps the commands it is given instead of turning a motor.
using var drive = new RecordingActuator();
// The rover's pose comes from integrating each command over half a second.
const float Dt = 0.5f;
using var rover = new SimulatedRobot(Dt);
// The soil probe reads around 31 percent, drying half a point a reading, with a
// wobble drawn from a seed, so the same seed gives the same readings every run.
using var soil = new SimulatedSensor(31.0f, -0.5f, 0.3f, 7);
// The radio loses every third report on its way to the base.
using var station = new LoopbackBroker();
using Transport radio = Transport.Degraded(station.Rung(), dropEvery: 3);
await radio.ConnectAsync();

List<float> moisture = [];
int delivered = 0;
while (true)
{
    // A replay that has handed back every reading reports that it is closed.
    float clear;
    try
    {
        clear = await ahead.ReadAsync();
    }
    catch (PamojaException error)
    {
        Console.WriteLine($"ahead     ran out after {moisture.Count} readings: {error.Message}");
        break;
    }

    (float speed, float turn) = clear > 1.0f ? (1.0f, 0.0f) : (0.0f, 1.0f);
    await drive.ApplyAsync(speed);
    await rover.ApplyAsync(new Twist(speed, Omega: turn));
    float wet = await soil.ReadAsync();
    float elapsed = moisture.Count * Dt;
    moisture.Add(wet);
    string report = Tenths(wet);
    try
    {
        await radio.SendAsync("vineyard/row-4/soil", report);
        delivered++;
    }
    catch (PamojaException)
    {
    }

    Console.WriteLine(
        $"{Tenths(elapsed)} s     {Tenths(clear)} m clear:"
        + $" drive {Tenths(speed)}, turn {Tenths(turn)}, soil {report}");
}

// The drive kept every command, which is how a test says what the loop decided
// rather than only what it ended up doing.
Console.WriteLine($"drive     recorded {string.Join(", ", drive.Commands.Select(Tenths))}");

// Three half-second commands at 1 m/s reach 1.5 m along x. The last turns on
// the spot at 1 rad/s for half a second, which moves the rover nowhere.
Pose pose = rover.Pose;
Console.WriteLine(
    $"rover     ended at x {Tenths(pose.X)} m, y {Tenths(pose.Y)} m, heading {Tenths(pose.Theta)} rad");

// A second probe with the same seed reads exactly the same values.
using var twin = new SimulatedSensor(31.0f, -0.5f, 0.3f, 7);
List<float> again = [];
foreach (float _ in moisture)
{
    again.Add(await twin.ReadAsync());
}

string verdict = again.SequenceEqual(moisture) ? "the same" : "different";
Console.WriteLine($"soil      a probe with the same seed read {verdict} {again.Count} values");
Console.WriteLine($"radio     delivered {delivered} of {moisture.Count} soil reports and lost the third");

The same capability in every language

Documentation

• Pamoja.Sim reference, every type in this namespace.
• The Simulators guide, with the same example in Rust, TypeScript, and Python.
• Every capability, and the install page.

License

MIT