8.1.2.2 Stability Enhancements

The auxiliary parameter aux.repeatlevel signals how often an execution of MINIMOS-NT already failed during prior attempts. It is used to switch off the usage of an initialization file or to switch to more robust numerical algorithms of the simulator (see also line Nr. 24 of Example 8.3 ), depending on the number of prior failures. This possibility is of considerable importance for the stability and the effectiveness of the optimization procedure, since it is necessary to escape situations where the device simulation is not able to converge, which might result from unrealistic fabrication parameters occurring during an intermediate stage of the optimization procedure. On the other hand, one is forced to use algorithms which accomplish good speed performance, while tending to be less robust, in order to keep the computation effort at a minimum.