public void WorksWithSinus()
{
// arrange
Func <double, double> func = Math.Sin;
// act
double actual = IntegralCalculus.Calculate(func, 0, Math.PI, 0.01);
// assert
Assert.InRange(actual, 1.99, 2.01);
}
public void WorksWithPolynomialFunction()
{
// arrange
Func <double, double> func = PolynomialFunction;
// act
double actual = IntegralCalculus.Calculate(func, 5.4, 6.7, 0.01);
// assert
Assert.InRange(actual, 162.75975, 162.77975);
}
private double Integrate(
string expression,
double lowerLimit,
double upperLimit,
IntegralCalculus.IntegrationAlgorithm integrationAlgorithm,
double numberOfIntervals = 100000)
{
Func <double, double> function = x => EvaluateExpression(expression, x);
var result = IntegralCalculus.Integrate(
function,
lowerLimit,
upperLimit,
integrationAlgorithm,
numberOfIntervals);
return(result);
}
public double Int(Func <double, double> func, double lowerLimit, double upperLimit)
{
return(IntegralCalculus.Integrate(func, lowerLimit, upperLimit));
}
public double Int(string expr, double lowerLimit, double upperLimit)
{
var expression = _parser.GetTokens(expr);
return(IntegralCalculus.Integrate(x => Eval(expression, x), lowerLimit, upperLimit));
}
/// <summary>
/// </summary>
/// <param name="x"></param>
/// <returns></returns>
public static double Erf(double x)
{
return(Constants.TwoOverSqrtOfPI * IntegralCalculus.Integrate(t => Math.Pow(Math.E, -(t * t)), 0, x));
}