static int Main()
{
// Load data (not from file...)
vector t = new vector(new double[] { 1, 2, 3, 4, 6, 9, 10, 13, 15 });
vector A = new vector(new double[] { 117, 100, 88, 72, 53, 29.5, 25.2, 15.2, 11.1 });
vector dA = new vector(A.size); // uncertainty of A
for (int i = 0; i < A.size; i++)
{
dA[i] = 0.05; // 5% uncertainty
}
// Transform data from y = a*exp(-lambda*t) --> ln(y) = ln(a) - lambda*t
for (int i = 0; i < A.size; i++)
{
dA[i] = dA[i] / A[i]; // delta ln(y) --> (delta y )/ y
A[i] = Log(A[i]);
}
// Make function array
Func <double, double>[] funcs = new Func <double, double>[] { x => 1, x => x };
// t -> 1 is for ln(a), t -> t is for lambda
// Make fit
Fit FitResult = qr_stuff.qrFitter(t, A, dA, funcs);
vector cErrors = FitResult.getParamErrors();
double a = Exp(FitResult.c[0]);
double aErr = cErrors[0];
double lambda = -FitResult.c[1];
double lambdaErr = cErrors[1];
// Generate Answer to answer questions:
FitResult.c.print("Fit result parameters: ");
WriteLine($"This means that a: {a} and lambda: {lambda}");
WriteLine($"This gives a half life of {Log(2)/lambda} days");
WriteLine("The half life of Ra224 is actually around 3.6319 days");
WriteLine("");
FitResult.cov.print("The Covariance matrix is estimated to");
cErrors.print("This give the following errors of the parameters");
WriteLine($"Thus, the half of ThX is estimated to be between {Log(2)/lambda} +- {Log(2)/lambda/lambda*lambdaErr} days");
// Generate plotting data to plot with
TextWriter DataWriter = Error;
//DataWriter.WriteLine("This is in the data stream");
for (double x = 0; x < 16; x += 1.0 / 16)
{
DataWriter.WriteLine($"{x} {Exp(FitResult.evaluate(x))} {Exp(FitResult.upper(x))} {Exp(FitResult.lower(x))}");
}
return(0);
}
