private static void makeseminfweights(GaussIntType pickmethod, int num, out double[] x, out double[] w,
double delta)
{
double[] xtemp, wtemp;
x = new double[num];
w = new double[num];
if (pickmethod == GaussIntType.GINTEQUAL)
{
for (int i = 0; i < num; i++)
{
x[i] = delta * (i + 1.0);
w[i] = delta;
}
}
else if (pickmethod == GaussIntType.GINTGLEG)
{
xtemp = new double[num + 1];
wtemp = new double[num + 1];
gauleg(0.0, 1.0, xtemp, wtemp, num / 2); // Gauss-Legendre weights & nodes
for (int i = 0; i < num; i++)
{
if (i < num / 2)
{
x[i] = delta * xtemp[i + 1];
w[i] = delta * wtemp[i + 1];
}
else
{
x[i] = delta / xtemp[num - i];
w[i] = delta * wtemp[num - i] / (xtemp[num - i] * xtemp[num - i]);
}
}
}
else if (pickmethod == GaussIntType.GINTGLEGTAN)
{
makearbweights(pickmethod, num, out xtemp, out wtemp, -1.0, +1.0);
for (int i = 0; i < num; i++)
{
x[i] = delta * Math.Tan(0.25 * Math.PI * (xtemp[i] + 1.0));
double tmp = 1.0 / Math.Cos(0.25 * Math.PI * (xtemp[i] + 1.0));
double s = delta * 0.25 * Math.PI * wtemp[i];
w[i] = s * tmp * tmp;
}
}
}
public static void makearbweights(GaussIntType pickmethod, int num, out double[] x, out double[] w, double xmin, double xmax)
{
double[] xtemp, wtemp;
int i;
x = new double[num];
w = new double[num];
if (pickmethod == GaussIntType.GINTEQUAL)
for (i = 0; i < num; i++)
{
x[i] = xmin + (xmax - xmin) * (i + 0.5) / num;
w[i] = (xmax - xmin) / num;
}
else if (pickmethod == GaussIntType.GINTGLEG || pickmethod == GaussIntType.GINTGLEGTAN)
{
xtemp = new double[num + 1];
wtemp = new double[num + 1];
gauleg(xmin, xmax, xtemp, wtemp, num);
double test = 0.0;
for (i = 0; i < num; i++)
{
x[i] = xtemp[i + 1];
w[i] = wtemp[i + 1];
test += w[i];
}
// cout + "with xmin="+xmin+" and xmax="+xmax+" int="+test+"\n";
}
}
