/// Create an instance of the receiver with parameters estimated from
/// the given histogram using best guesses. This method can be used to
/// find the initial values for a fit.
/// @param h DhbScientificCurves.Histogram
/// @exception ArgumentOutOfRangeException
/// when no suitable parameter can be found.
public WeibullDistribution(Histogram h)
{
if (h.Minimum < 0)
throw new ArgumentOutOfRangeException(
"Weibull distribution is only defined for non-negative values");
double average = h.Average;
if (average <= 0)
throw new ArgumentOutOfRangeException(
"Weibull distribution must have a non-negative average");
double xMin = (h.Minimum + average) * 0.5;
double accMin = System.Math.Log(-System.Math.Log(1 - h.CountsUpTo(xMin) / h.TotalCount));
double xMax = (h.Maximum + average) * 0.5;
double accMax = System.Math.Log(-System.Math.Log(1 - h.CountsUpTo(xMax) / h.TotalCount));
double delta = accMax - accMin;
xMin = System.Math.Log(xMin);
xMax = System.Math.Log(xMax);
DefineParameters(delta / (xMax - xMin),
System.Math.Exp((accMax * xMin - accMin * xMax) / delta));
}
