/// <summary>
/// Creates a hyperbolic orbit around the given celestial body.
/// </summary>
/// <returns>The newly created orbit, with state vectors anchored to its periapsis.</returns>
/// <param name="body">The celestial body at the focus of the orbit.</param>
/// <param name="periapsis">The periapsis (from the body center), in meters. Must not be
/// negative.</param>
/// <param name="vInf">The excess speed associated with the orbit, in meters per second.
/// Must be positive.</param>
/// <param name="utPeri">The absolute time of periapsis passage.</param>
///
/// <exception cref="ArgumentException">Thrown if either <c>periapsis</c> or <c>vInf</c>
/// are out of bounds.</exception>
static Orbit createHyperbolicOrbit (CelestialBody body, double periapsis, double vInf,
double utPeri)
{
if (vInf <= 0.0) {
throw new ArgumentException (
Localizer.Format ("#autoLOC_CustomAsteroids_ErrorHyperBadVInf", vInf),
nameof (vInf));
}
if (periapsis < 0.0) {
throw new ArgumentException (
Localizer.Format ("#autoLOC_CustomAsteroids_ErrorHyperBadPeri", periapsis),
nameof (periapsis));
}
double a = -body.gravParameter / (vInf * vInf);
double e = 1.0 - periapsis / a;
// Random orientation, to be consistent with CreateRandomOrbitFlyBy
double i = RandomDist.drawIsotropic ();
double lAn = RandomDist.drawAngle ();
double aPe = RandomDist.drawAngle ();
Debug.Log ($"[CustomAsteroids]: "
+ Localizer.Format ("#autoLOC_CustomAsteroids_LogHyperOrbit", body.bodyName,
a, e, i, aPe, lAn));
return new Orbit (i, e, a, lAn, aPe, 0.0, utPeri, body);
}
/// <summary>
/// Generates a random number consistent with the distribution. The program state shall be
/// unchanged in the event of an exception.
/// </summary>
/// <returns>The desired random variate. The distribution depends on this object's internal
/// data.</returns>
///
/// <exception cref="ArgumentException">Thrown if the parameters are inappropriate
/// for the distribution.</exception>
/// <exception cref="InvalidOperationException">Thrown if the distribution is
/// invalid.</exception>
internal double draw()
{
switch (dist)
{
case Distribution.Uniform:
return(RandomDist.drawUniform(min, max));
case Distribution.LogUniform:
return(RandomDist.drawLogUniform(min, max));
case Distribution.Gaussian:
case Distribution.Normal:
return(RandomDist.drawNormal(avg, stdDev));
case Distribution.LogNormal:
if (avg <= 0.0)
{
throw new ArgumentException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorLogNormMean", avg));
}
if (stdDev <= 0.0)
{
throw new ArgumentException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorLogNormStd", stdDev));
}
double quad = Math.Sqrt(avg * avg + stdDev * stdDev);
double mu = Math.Log(avg * avg / quad);
double sigma = Math.Sqrt(2 * Math.Log(quad / avg));
return(RandomDist.drawLognormal(mu, sigma));
case Distribution.Rayleigh:
return(RandomDist.drawRayleigh(avg * Math.Sqrt(2.0 / Math.PI)));
case Distribution.Exponential:
return(RandomDist.drawExponential(avg));
case Distribution.Gamma:
if (avg <= 0.0)
{
throw new ArgumentException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorGammaMean", avg));
}
if (stdDev <= 0.0)
{
throw new ArgumentException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorGammaStd", stdDev));
}
double k = (avg / stdDev);
k = k * k;
double theta = stdDev * stdDev / avg;
return(RandomDist.drawGamma(k, theta));
case Distribution.Beta:
if (avg <= min || avg >= max)
{
throw new ArgumentException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorBetaMean", min, avg, max));
}
if (stdDev <= 0.0)
{
throw new ArgumentException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorBetaStd", stdDev));
}
double scaledMean = (avg - min) / (max - min);
double scaledStdDev = stdDev / (max - min);
double scaledVar = scaledStdDev * scaledStdDev;
double factor = (scaledMean - scaledMean * scaledMean - scaledVar) / scaledVar;
double alpha = scaledMean * factor;
double beta = (1.0 - scaledMean) * factor;
return(min + (max - min) * RandomDist.drawBeta(alpha, beta));
case Distribution.Isotropic:
return(RandomDist.drawIsotropic());
default:
throw new InvalidOperationException(
Localizer.Format("#autoLOC_CustomAsteroids_ErrorBadDistribution", dist));
}
}
