static int Main()
{
int n = 40;
int N = 100;
double[] x = new double[n];
double[] y = new double[n];
int i;
//change
for (i = 0; i < n; i++)
{
x[i] = 2 * PI * i / (n - 1);
y[i] = Sin(x[i]);
//WriteLine("equidistant points of sine {0:g6} {1:g6}", x[i],y[i]);
}
Write("\n");
var cs = new cspline(x, y);
var qua = new quadspline(x, y);
var cub = new cubespline(x, y);
double z = x[0];
double step = (x[n - 1] - x[0]) / (N - 1);
for (i = 0; i < N; i++)
{
z = x[0] + i * step;
WriteLine($"{z} {cs.eval(z)} {cs.integ(z)} {qua.eval(z)} {qua.integ(z)} {qua.derive(z)} {cub.eval(z)} {cub.integ(z)} {cub.derive(z)}");
}
// Write($"test integration of sine from 0 to 2pi: {cs.integ(2*PI)}\n");
// Write($"evaluate interpol sin at pi/2, pi: {cs.eval(PI/2)} {cs.eval(PI)}\n");
return(0);
}
public static int Main(string[] args)
{
if (args.Length != 2)
{
return(1);
}
// The two input parameters will be the name of the file with the table values
// and the amount of lines in that file
string filein = args[0];
int nlines = int.Parse(args[1]);
StreamReader streamin = new StreamReader(filein);
double[] xs = new double[nlines];
double[] ys = new double[nlines];
for (int i = 0; i < nlines; i++)
{
string line = streamin.ReadLine();
// There is a third value in each line (the integral from x[0] to z), but we
// do not need the value here
string[] numbers = line.Split('\t');
xs[i] = double.Parse(numbers[0]);
ys[i] = double.Parse(numbers[1]);
}
streamin.Close();
// Interpolate the data
double xstart = xs[0];
double xend = xs[nlines - 1];
double deltax = 0.02;
var qspline = new quadspline(xs, ys);
for (double k = xstart; k < xend; k += deltax)
{
double interpval = qspline.eval(k);
double integralval = qspline.integrate(k);
double derivval = qspline.deriv(k);
WriteLine("{0,8:f4}\t{1,8:f4}\t{2,8:f4}\t{3,8:f4}", k, interpval, integralval, derivval);
}
return(0);
}