static List <double> quadratic(Sums s, double[] X, double[] Y)
{
double[] coefficient = new double[3];
double[,] sys_matrix = { { s.sum4(X), s.sum3(X), s.sum2(X) },
{ s.sum3(X), s.sum2(X), s.sum(X) },
{ s.sum2(X), s.sum(X), X.Length } };
double[] solution_row = { s.sum_x_x_mult_y(X, Y), s.sum_x_mult_y(X, Y), s.sum(Y) };
alglib.rmatrixsolve(sys_matrix, 3, solution_row, out int t, out alglib.densesolverreport c, out coefficient);
List <double> cof = new List <double>();
cof.AddRange(coefficient);
return(cof);
}
static List <double> exponential(Sums s, double[] X, double[] Y)
{
double[] coefficient = new double[2];
double[,] sys_matrix = { { s.sum2(X), s.sum(X) },
{ s.sum(X), X.Length } };
double[] solution_row = { s.sum_y_on_log_x(X, Y), s.sum_log_x(Y) };
alglib.rmatrixsolve(sys_matrix, 2, solution_row, out int t, out alglib.densesolverreport c, out coefficient);
coefficient[1] = Math.Exp(coefficient[1]);
List <double> cof = new List <double>();
cof.AddRange(coefficient);
return(cof);
}