//Default grid with 1, 2 end 4 steps
private int CalcOptStepCqf(double start, double end, double accuracy, TypeOfCqf typeOfCqf)
{
var defaultIntegralsValue = new[] { CalcIntegralCqf(start, end, 1, typeOfCqf), CalcIntegralCqf(start, end, 2, typeOfCqf), CalcIntegralCqf(start, end, 4, typeOfCqf) };
var aitkinConstant = CalcAitkinConstant(defaultIntegralsValue, new [] { 1, 2, 4 });
var defaultStepsRelation = 2;
var optimalStepSize = 1.0 / 2 * Math.Pow(accuracy * (1 - Math.Pow(defaultStepsRelation, -aitkinConstant)) / Math.Abs(defaultIntegralsValue[2] - defaultIntegralsValue[1]), (double)1 / aitkinConstant);
return((int)(1.0 / optimalStepSize));
}
private double CalcIntegralCqf(double start, double end, int parts, TypeOfCqf typeOfCqf)
{
var integralValue = 0.0;
var sizeOfStep = (end - start) / parts;
for (var i = 0; i < parts; i++)
{
double[] nodes;
switch (typeOfCqf)
{
case TypeOfCqf.Iqf:
nodes = new double[3];
nodes[0] = start + sizeOfStep * i;
nodes[1] = start + sizeOfStep * (i + 1.0 / 2);
nodes[2] = start + sizeOfStep * (i + 1);
integralValue += _iqfHelper.CalcIntegral(nodes[0], nodes[2], nodes);
break;
case TypeOfCqf.Gqf:
nodes = new double[2];
nodes[0] = start + sizeOfStep * i;
nodes[1] = start + sizeOfStep * (i + 1);
integralValue += _gqfHelper.CalcIntegral(nodes[0], nodes[1]);
break;
default:
throw new ArgumentOutOfRangeException(nameof(typeOfCqf), typeOfCqf, null);
}
}
return(integralValue);
}
public double CalcIntegralWithAccuracy(double start, double end, double accuracy, TypeOfCqf typeOfCqf)
{
var steps = CalcOptStepCqf(start, end, accuracy, typeOfCqf);
var arrayWithSteps = new[] { steps };
var integralValues = new[] { CalcIntegralCqf(start, end, steps, typeOfCqf) };
var currentAccuracy = Double.MaxValue;
while (currentAccuracy > accuracy)
{
steps *= 2;
var newIntegralValue = CalcIntegralCqf(start, end, steps, typeOfCqf);
integralValues = AddValueToArray(integralValues, newIntegralValue);
arrayWithSteps = AddValueToArray(arrayWithSteps, steps);
currentAccuracy = CalcAccuracyRichardson(integralValues, arrayWithSteps, start, end);
}
return(integralValues.Last());
}
