public void Test_coulomb_energy_element()
{
matrix A = new matrix("2.0,0.3;0.3,4.8");
matrix B = new matrix("6.7,4.2;4.2,0.8");
double V12 = -0.1431627118230019 * mef.overlapElement(A, B);
double V13 = 0.1431627118230019 * mef.overlapElement(A, B);
double V23 = -0.0881622593246209 * mef.overlapElement(A, B);
double result = mef.coulombPotentialEnergy(A, B);
double ans = V12 + V13 + V23;
Assert.AreEqual(ans, result);
}