How to normalize eigenvectors

Roofit and RooStats
1

So, I’ve got: TMatrixD M(3, 3); // ... here all "M" elements are initialized ... // ... "M" is used just to get "eval" and "evec" ... TVectorD eval; TMatrixD evec(TMatrixD::kTransposed, M.EigenVectors(eval)); // ... "M" is not used any more ... and the problem is that the “evec” matrix contains unnormalized eigenvectors.
What is the [color=#FF0000]simplest[/color] way to get “normalized eigenvectors”?

2 
for (Int_t ir = 0; ir < evec.GetNrows(); ir++)
{
  const TVectorD v = TMatrixDRow_const(evec,ir);
  const Double_t norm = TMath::Sqrt(v.Norm2Sqr());
  TMatrixDRow(evec,ir) *= 1/norm;
}