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Table 13-3. Optimization Result Status Code (cont.)
Message and meaning
Optimization
Final Diagnostic Conditions
2 The current point cannot be improved. A sufficient decrease in the merit function
could not be attained during the last line search. This may occur because the user
has requested an overly stringent accuracy.
A sufficient decrease in the merit function could not be attained during the final
line search. This sometimes occurs because an overly stringent accuracy has been
requested, that is, TOL_OPT is too small. In this case verify the following to
determine whether or not the final solution is acceptable:
• The final values of Optimality are significantly small.
• The final values of Feasibility are significantly small. This is set to zero if there
are no equality or inequality constraints.
An additional status code may be raised, of value: 0, 6, or 11.
4 Optimization was not successful. The maximum number of simulation runs has
been reached.
The limiting number of simulations, determined by the optional parameter
MAX_SIMUL has been reached.
6 The current point is feasible and quite optimal, however, the required accuracy has
not been achieved. The optimizer is within 1e-2 of satisfying the TOL_OPT (or
TOL_GRAD) optimality tolerance.
The optimizer is within 1x10 −2 of satisfying the TOL_OPT (or TOL_GRAD)
optimality tolerance. For the next runs, check that TOL_OPT is not too small.
7 The objective function may be unbounded on the feasible set. Alternatively, it may
happen that the scaling of the problem is very poor.
To avoid this situation, if the MINIMIZE or MAXIMIZE objectives are close to
singularities, define bounds on some variables. Also use an appropriate scaling of
the design objectives.
8 The simulation process stopped the optimization. The optimization was
abandoned.
This message is raised only after an interrupt message (Ctrl+C).
9 The current point cannot be improved. The problem is too hard to solve. Try with
another starting point.
This has to be considered as a failure of the optimizer regarding the treatment of
constraint feasibilities. Please refer to “Normal and Elastic Modes of Termination”
on page 659. Check that the final solution is not an acceptable point for the
problem.
10 The current point cannot be improved. The Hessian matrix has been reset too many
times. It indicates that the line search failed to find a sufficiently better point for a
large number of iterations.
This message should appear very rarely. This is an algorithmic weakness of the
method implemented in the Eldo optimizer SQP method. Try to start the
optimization from a different point.
Eldo® User's Manual, 15.3 657