743
743
// RealScalar e2 = abs2(subdiag[end-1]);
744
744
// RealScalar mu = diag[end] - e2 / (td + (td>0 ? 1 : -1) * sqrt(td*td + e2));
745
745
// This explain the following, somewhat more complicated, version:
748
757
RealScalar x = diag[start] - mu;
749
758
RealScalar z = subdiag[start];