Search Types

At present there are eight possible search types corresponding to eigenvector-following and quadratic steepest descent, represented by the internal variable INR, with allowed values ranging from 0 to 7. The two most common types are 0, for minimization, and 2, for transition state searching. The steps have the same form in both cases,[36] except that we go downhill in every direction when minimizing, and uphill in one direction when looking for a transition state. For these search types convergence to stationary points with the wrong Hessian index (i.e. not 0 or 1 negative Hessian eigenvalues, respectively) is detected and countermeasures are taken as specified below.