/// <summary>
/// Generate a list of SystemBody instances from a CSV string. This method will convert positions and
/// velocities from KM and KM/s to M and M/s.
/// </summary>
/// <param name="inputCSV">The input CSV string.</param>
/// <returns>A list of SystemBody instances.</returns>
public static List <SystemBody> BodyListFromCSV(string inputCSV)
{
List <SystemBody> bodyList = new List <SystemBody>();
string[] lineSplitCSV = inputCSV.Split('\n');
foreach (string line in lineSplitCSV)
{
NumberStyles numberStyle = NumberStyles.AllowLeadingSign | NumberStyles.AllowDecimalPoint | NumberStyles.AllowExponent;
string[] commaSplitCSV = line.Trim('\n').Trim('\r').Split(',');
string name = commaSplitCSV[0];
double mass = double.Parse(commaSplitCSV[1], numberStyle);
double x = double.Parse(commaSplitCSV[2], numberStyle) * 1000;
double y = double.Parse(commaSplitCSV[3], numberStyle) * 1000;
double z = double.Parse(commaSplitCSV[4], numberStyle) * 1000;
double vx = double.Parse(commaSplitCSV[5], numberStyle) * 1000;
double vy = double.Parse(commaSplitCSV[6], numberStyle) * 1000;
double vz = double.Parse(commaSplitCSV[7], numberStyle) * 1000;
SystemBody systemBody = new SystemBody(name, mass, x, y, z, vx, vy, vz);
bodyList.Add(systemBody);
}
return(bodyList);
}
/// <summary>
/// Write the final simulation data to an output CSV file. The output file will be overwritten for
/// each simulation with an identical timestep.
/// </summary>
/// <param name="system">The simulated system.</param>
public static void BodyListToCSV(System system)
{
List <string> csv = new List <string>();
List <SystemBody> simulatedBodies = system.CurrentState.OrderBy(body => body.Name).ToList();
List <SystemBody> realBodies = system.IdealEndState.OrderBy(body => body.Name).ToList();
for (int i = 0; i < simulatedBodies.Count; i++)
{
SystemBody simulatedBody = simulatedBodies[i];
SystemBody realBody = realBodies[i];
double errorX = Math.Abs((simulatedBody.X - realBody.X) / realBody.X) * 100;
double errorY = Math.Abs((simulatedBody.Y - realBody.Y) / realBody.Y) * 100;
double errorZ = Math.Abs((simulatedBody.Z - realBody.Z) / realBody.Z) * 100;
double errorDisplacement = (errorX + errorY + errorZ) / 3.0;
double errorVX = Math.Abs((simulatedBody.VX - realBody.VX) / realBody.VX) * 100;
double errorVY = Math.Abs((simulatedBody.VY - realBody.VY) / realBody.VY) * 100;
double errorVZ = Math.Abs((simulatedBody.VZ - realBody.VZ) / realBody.VZ) * 100;
double errorVelocity = (errorVX + errorVY + errorVZ) / 3.0;
double trueError = (errorDisplacement + errorVelocity) / 2.0;
csv.Add($"{simulatedBody.Name},{errorDisplacement},{errorVelocity},{trueError}");
}
File.WriteAllLines($"output_{system.DT}dt.csv", csv.ToArray());
}
/// <summary>
/// Calculate the distance between the current body and another body.
/// </summary>
/// <param name="other">The other body with which to determine distance.</param>
/// <returns>The distance between the two bodies.</returns>
public double DistanceBetween(SystemBody other)
{
return
(Math.Sqrt(
Math.Pow(this.X - other.X, 2) +
Math.Pow(this.Y - other.Y, 2) +
Math.Pow(this.Z - other.Z, 2)
));
}
/// <summary>
/// Simulation entry point.
/// </summary>
/// <param name="args">
/// Command line arguments; the first is the path to the starting state CSV file, the second
/// is the path to the ending state CSV file.
/// </param>
public static void Main(string[] args)
{
string initialStateCSV = File.ReadAllText(args[0]);
string idealEndStateCSV = File.ReadAllText(args[1]);
double dt = double.Parse(args[2], NumberStyles.AllowDecimalPoint);
List <SystemBody> initialState = BodyListFromCSV(initialStateCSV);
List <SystemBody> idealEndState = BodyListFromCSV(idealEndStateCSV);
System system = new System(initialState, idealEndState, dt);
system.Integrate();
system.AdjustBarycenter();
foreach (SystemBody body in system.CurrentState)
{
SystemBody realBody = system.IdealEndState.Where(m => m.Name == body.Name).ToList()[0];
Console.WriteLine($"{body.Name},{body.X},{body.Y},{body.Z}");
Console.WriteLine($"{realBody.Name},{realBody.X},{realBody.Y},{body.Z}");
}
BodyListToCSV(system);
}
/// <summary>
/// Calculate the distance between the current body and another body with respect to
/// the Z component of position.
/// </summary>
/// <param name="other">The other body with which to determine distance.</param>
/// <returns>The distance between the two bodies, with respect to the Z component.</returns>
public double DistanceBetweenZ(SystemBody other)
{
return
(this.Z - other.Z);
}
/// <summary>
/// Calculate the distance between the current body and another body with respect to
/// the Y component of position.
/// </summary>
/// <param name="other">The other body with which to determine distance.</param>
/// <returns>The distance between the two bodies, with respect to the Y component.</returns>
public double DistanceBetweenY(SystemBody other)
{
return
(this.Y - other.Y);
}
/// <summary>
/// Calculate the distance between the current body and another body with respect to
/// the X component of position.
/// </summary>
/// <param name="other">The other body with which to determine distance.</param>
/// <returns>The distance between the two bodies, with respect to the X component.</returns>
public double DistanceBetweenX(SystemBody other)
{
return
(this.X - other.X);
}
