//получение собственных значений матрицы
private static double[] GetEigenValues(double[] p, int numberOfRoots)
{
//по формуле, при построении полинома знаки коэфициентов около всех степеней, кроме старшей, меняются
var SignChangedCoefs = p.Select(v => - v).ToList();
//добавляем 1 для старшей степени
SignChangedCoefs.Insert(0, 1);
//return EquationSolver.GetRoots(SignChangedCoefs.ToArray(), 0.00000001, 0.1);
return(EquationSolver.GetRoots(SignChangedCoefs.ToArray(), numberOfRoots));
}
public void GetRoots_TwoZeroCoefficients_Return1Root()
{
//arrange
double determinant = 0;
double[] coefficients = new[] { 2.0, 0, 0 };
EquationSolver equationSolver = new EquationSolver();
//act
double[] roots = equationSolver.GetRoots(determinant, coefficients);
//assert
Assert.AreEqual(new[] { 0, 0 }, roots);
}
public void GetRoots_ThreeNegativeCoefficients_Return2Roots()
{
//arrange
double determinant = 1;
double[] coefficients = new[] { -4.0, -9, -5 };
EquationSolver equationSolver = new EquationSolver();
//act
double[] roots = equationSolver.GetRoots(determinant, coefficients);
//assert
Assert.AreEqual(new[] { -1.25, -1 }, roots);
}
public void GetRoots_OneZeroCoefficient_Return2Roots()
{
//arrange
double determinant = 25;
double[] coefficients = new[] { 2.0, 5, 0 };
EquationSolver equationSolver = new EquationSolver();
//act
double[] roots = equationSolver.GetRoots(determinant, coefficients);
//assert
Assert.AreEqual(new[] { 0, -2.5 }, roots);
}
public void GetRoots_ThreePositiveCoefficients_Return2Roots()
{
//arrange
double determinant = 9;
double[] coefficients = new[] { 2.0, 5, 2 };
EquationSolver equationSolver = new EquationSolver();
//act
double[] roots = equationSolver.GetRoots(determinant, coefficients);
//assert
Assert.AreEqual(new[] { -0.5, -2 }, roots);
}
