private double CalculateQuadratureCoef(int index, double[] solutions, int n)
{
double Ai = 0;
MathFunction func = new ConstFunction(1.0d);
for (int i = 0; i <= n; i++)
{
if (i != index)
{
func *= (new XFunction(1.0d) - solutions[i]) / (solutions[index] - solutions[i]);
}
}
Ai = func.CalculateDeterminedIntegral(new SimpsonMethod(), -1, 1, powerForIntegralCalculation);
return(Ai);
}
public virtual MathFunction Derivative(int order)
{
if (functions.Count == 0)
{
throw new Exception("Function is empty!");
}
if (order < 0)
{
throw new Exception("Incorrect derivative order!");
}
if (order == 0)
{
return(new MathFunction(coef, type, functions.ToArray()));
}
MathFunction result = 0.0d;
switch (type)
{
case MathFunctionType.Sum:
result = functions[0].Derivative(order);
for (int i = 1; i < functions.Count; i++)
{
result += functions[i].Derivative(order);
}
break;
case MathFunctionType.Multiplication:
result = new ConstFunction(0.0d);
for (int i = 0; i < functions.Count; i++)
{
MathFunction func = functions[i].Derivative(1);
for (int j = 0; j < functions.Count; j++)
{
if (i != j)
{
func *= functions[j];
}
}
result += func;
}
result = Derivative(order - 1);
break;
case MathFunctionType.Division:
MathFunction f = functions[0],
g = functions[1];
result = (f.Derivative(1) * g - g.Derivative(1) * f) / (g ^ 2);
result = Derivative(order - 1);
break;
}
return(result);
}
