/// <summary>
/// Gets Besselian elements values for specified Juluan Day.
/// </summary>
/// <param name="jd">Julian Day of interest.</param>
/// <returns>Besselian elements for the given instant.</returns>
public InstantLunarEclipseElements GetInstantBesselianElements(double jd)
{
//if (jd < From || jd > To)
// throw new ArgumentException($"Polynomial Besselian elements valid only for Julian Day in range [{From} ... {To}].", nameof(jd));
// difference, with t0, in step units
double t = (jd - JulianDay0) / Step;
return(new InstantLunarEclipseElements()
{
JulianDay = jd,
DeltaT = DeltaT,
X = X.Select((x, n) => x * Pow(t, n)).Sum(),
Y = Y.Select((y, n) => y * Pow(t, n)).Sum(),
F1 = F1.Select((y, n) => y * Pow(t, n)).Sum(),
F2 = F2.Select((y, n) => y * Pow(t, n)).Sum(),
F3 = F3.Select((y, n) => y * Pow(t, n)).Sum(),
Alpha = To360(Alpha.Select((y, n) => y * Pow(t, n)).Sum()),
Delta = Delta.Select((y, n) => y * Pow(t, n)).Sum(),
});
}
public void runBackward()
{
bool birthDecision = false;
bool converged = false;
double normaliser = 1.0;
// variables for capturing rate of increase in fitness
double r = 0.0;
double rPrev = 0.0;
int i = 0;
int motherAge = ageAtMaturity;
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
// main loop
do
{
motherAge = ageAtMaturity;
// loop over each permutation of mother's age and family index to find max. fitness
for (int arrayIndex = 0; arrayIndex < F1.Length; arrayIndex++)
{
for (int familyIndex = 0; familyIndex < numFamilies; familyIndex++)
{
if (StateSpace[arrayIndex, familyIndex])
{
F2[arrayIndex][familyIndex] = findFMax(motherAge, familyIndex, arrayIndex, ref birthDecision);
births[arrayIndex][familyIndex] = birthDecision;
// normalise the array
if (arrayIndex == 0 && familyIndex == 0) // only set normaliser (denominator) in first iteration
{
normaliser = F2[0][0]; // F2[0][0] is fitness when mother's age is 15 for first family structure
}
F2[arrayIndex][familyIndex] = F2[arrayIndex][familyIndex] / normaliser;
}
} // end of family index loop
motherAge += 1;
} // end of mother's age loop
// what is the population rate of increase?
r = normaliser / F1[0][0]; // use 'normaliser' because F2[0][0] gets 'normalised' above so result == 1 always
try
{
if (i >= 75)
{
if (rPrev.ToString().Substring(0, 7) == r.ToString().Substring(0, 7)) // match current and previous pop growth rates to 4th decimal place
{
Console.WriteLine("CONVERGED");
converged = true;
}
}
}
catch (Exception e) { }
rPrev = r;
// write to F1 for next time step
F1 = F2.Select(s => s.ToArray()).ToArray();
if (logger != null)
{
logger.WriteLine("Finished loop {0} in {1}; r={2}", i, stopwatch.Elapsed, r);
}
else
{
Console.WriteLine("Finished loop {0} in {1}; r={2}", i, stopwatch.Elapsed, r);
}
i++;
} while (!converged);
// end of main loop
stopwatch.Stop();
finishedBackward = true;
}