static void Main(){
int n=10, N=200;
double[] x = new double[n];
double[] y = new double[n];
int i;
for(i=1; i<n; i++){
x[i]=2*PI*i/(n-1);
y[i]=Sin(x[i]);
WriteLine("{0:g6} {1:g6}",x[i],y[i]);
}
Write("\n\n");
var ls = new lspline(x,y);
double z;
double step=(x[n-1]-x[0])/(N-1);
for(z=x[0],i=0;i<N;z=x[0]+(++i)*step){
WriteLine($"{z} {Sin(z)} {ls.eval(z)}");
}
Write("\n\n");
for(z=x[0],i=0;i<N;z=x[0]+(++i)*step){
WriteLine($"{z} {1-Cos(z)} {ls.integ(z)}");
}
}//Main
public static int Main()
{
// The interpolation routines will be tested on the function f(x) = sin(x)
double xmin = 0; // Minimum x value
double xmax = 3 * PI; // Maximum x value
misc.generate_data(f1, xmin, xmax, 0.5, "./datafiles/data.txt"); // Generate tabulated function values
misc.generate_data(f2, xmin, xmax, 0.5, "./datafiles/data2.txt"); // Generate tabulated integration values
misc.generate_data(f3, xmin, xmax, 0.5, "./datafiles/data3.txt"); // Generate tabulated integration values
// Load tabulated data values into double arrays
List <double[]> data = misc.load_data("./datafiles/data.txt");
double[] x = data[0];
double[] y = data[1];
int n = x.Length;
// Preparation of output files for plotting
var lspline_out = new System.IO.StreamWriter("./datafiles/lspline_out.txt", append: false);
var qspline_out = new System.IO.StreamWriter("./datafiles/qspline_out.txt", append: false);
var cspline_out = new System.IO.StreamWriter("./datafiles/cspline_out.txt", append: false);
var outfile = new System.IO.StreamWriter("./out.txt", append: false);
double dz = 0.01;
// Output files for linear interpolation
var res1 = new lspline(x, y);
for (double z = x[0]; z <= x[x.Length - 1]; z += dz)
{
lspline_out.WriteLine($"{z} {res1.spline(z)} {res1.integral(z)}");
}
lspline_out.Close();
// Output files for quadratic interpolation
var res2 = new qspline(x, y);
for (double z = x[0]; z <= x[x.Length - 1]; z += dz)
{
qspline_out.WriteLine($"{z} {res2.spline(z)} {res2.integral(z)} {res2.derivative(z)}");
}
qspline_out.Close();
// Output files for cubic interpolation
var res3 = new cspline(x, y);
for (double z = x[0]; z <= x[x.Length - 1]; z += dz)
{
cspline_out.WriteLine($"{z} {res3.spline(z)} {res3.integral(z)} {res3.derivative(z)}");
}
cspline_out.Close();
// Output files for comparsion of interpolation routines in terms of the integration values
outfile.WriteLine($"In the following, the interpolation routines are compared with their integration values.");
outfile.WriteLine($"For comparison, f(x) = sin(x) is interpolated and integrated from 0 to 2*pi (analytical value: 0).\n");
outfile.WriteLine($"Linear interpolation:");
outfile.WriteLine($"Integration result: {res1.integral(2*PI)}");
outfile.WriteLine($"Error: {0-res1.integral(2*PI)}\n");
outfile.WriteLine($"Quadratic interpolation:");
outfile.WriteLine($"Integration result: {res2.integral(2*PI)}");
outfile.WriteLine($"Error: {0-res2.integral(2*PI)}\n");
outfile.WriteLine($"Cubic interpolation:");
outfile.WriteLine($"Integration result: {res3.integral(2*PI)}");
outfile.WriteLine($"Error: {0-res3.integral(2*PI)}\n");
outfile.Close();
return(0);
}
static int Main(string[] args)
{
if (args.Length < 3)
{
Console.Error.WriteLine("too few arguments");
return(1);
}
string infile = args[0];
string outfile1 = args[1];
string outfile2 = args[2];
StreamReader instream = new StreamReader(infile);
StreamWriter outstream1 = new StreamWriter(outfile1, append: false);
StreamWriter outstream2 = new StreamWriter(outfile2, append: false);
//Importing the data into vectors
List <double> xlist = new List <double>();
List <double> ylist = new List <double>();
do
{
string line = instream.ReadLine();
if (line == null)
{
break;
}
string[] values = line.Split(' ', '\t');
xlist.Add(Double.Parse(values[0]));
ylist.Add(Double.Parse(values[1]));
} while (true);
int n = xlist.Count;
vector x = new vector(n);
vector y = new vector(n);
for (int i = 0; i <= (n - 1); i++)
{
x[i] = xlist[i];
y[i] = ylist[i];
}
lspline s = new lspline(x, y);
// The linear interpolation
int N = 999;
for (int i = 0; i <= N; i++)
{
double z = (x[n - 1] - x[0]) / N * i + x[0];
double yz = s.eval(z);
outstream1.WriteLine($"{z} \t {yz}");
}
// Intergrating by the linear interpolation
for (int i = 0; i <= N; i++)
{
double z = (x[n - 1] - x[0]) / N * i + x[0];
double area_z = s.integral(z);
outstream2.WriteLine($"{z} \t {area_z}");
}
outstream1.Close();
outstream2.Close();
instream.Close();
return(0);
}
