double DoubleIntegralCells(double X1, double X2, double Y1, double Y2, Double2Func Func)
{
double hx = (X2 - X1) / StepsXCount,
hy = (Y2 - Y1) / StepsYCount,
x = X1, y = Y1,
Result = 0.0;
for (int i = 0; i < StepsYCount; i++, y += hy, x = X1)
{
for (int j = 0; j < StepsXCount; j++, x += hx)
{
Result += Func(x - hx * 0.5, y - hy * 0.5);
}
}
return(Result * hx * hy);
}
double DoubleIntegral(double X1, double X2, double Y1, double Y2, double[] LegendreRoots, double[] GaussCoefs, Double2Func Func)
{
double Result = 0;
for (int i = 0; i < GaussCoefs.Length; i++)
{
double X = ((X2 + X1) + (X2 - X1) * LegendreRoots[i]) * 0.5;
for (int j = 0; j < GaussCoefs.Length; j++)
{
double Y = ((Y2 + Y1) + (Y2 - Y1) * LegendreRoots[j]) * 0.5;
Result += GaussCoefs[i] * GaussCoefs[j] * Func(X, Y);
}
}
Result *= (X2 - X1) * (Y2 - Y1) * 0.25;
return(Result);
}