// compute the eigen vectors
if(computeEigenvectors)
{
if((eivals(1)-eivals(0))<=Eigen::NumTraits<Scalar>::epsilon())
eivecs.setIdentity();
}
else {
scaledMat.diagonal().array () -= eivals(1);
Scalar a2 = numext::abs2(scaledMat(0,0));
Scalar c2 = numext::abs2(scaledMat(1,1));
eivecs.col(0) << eivecs.col(1).unitOrthogonal();
// Rescale back to the original size.