Configuring the Sequential Quadratic Programming (NLPQLP) Technique

Select the optimization technique as described in Configuring the Technique and Execution Options.

In the Optimization Technique Options area, enter or select the following:

Option	Description
Max Iterations	This parameter sets the maximum number of design iterations you want the optimizer to run. The value type is integer. The default value is 40. Other possible values are $\geq 1$ .
Termination Accuracy	This parameter sets the termination criterion for NLPQLP. The NLPQLP stopping algorithm uses several alternative convergence checks, with the main convergence parameter based on the Karush-Kuhn-Tucker necessary optimality condition and the complementary slackness. Termination accuracy is applied in such a way that the scale of the objective and constraint parameters has little or no effect on the convergence check. The accuracy of the gradients calculation must be considered when selecting the Termination Accuracy value. If the subflow outputs are accurate up to 8–10 digits and the calculated gradients have at least 7 accurate digits, the recommended Termination Accuracy value is $1 \times 10^{7}$ . If the gradient’s accuracy is lower, the Termination Accuracy value must be increased to $1.0 \times 10^{- 5} ...1.0 \times 10^{- 4}$ . The value type is real. The default value is $1 \times 10^{- 6}$ . Other possible values are $0 \leq T e r m i n a t i o n A c c u r a c y \leq 1.0$ .
Rel Step Size	This parameter sets the relative finite difference step size for the creation of the linear model. The value type is real. The default value is 0.0010 (0.1%). Other possible values are > 0.0.
Min Abs Step Size	This parameter sets the minimum absolute finite difference step for the creation of the linear model. The value type is real. The default value is $1 \times 10^{- 4}$ . Other possible values are $> 0.0$ .
Gradient Points	NLPQL supports higher-order gradient approximation formulas, increasing the number of points which are evaluated in parallel and the accuracy of the approximation. Gradient Points is an integer specifying the number of additional points (per design variable) that will be evaluated during the gradient calculation. A value of 1 corresponds to the standard forward-difference formulation [f(x+h)- f(x)]/h; a value of 2 corresponds to the slightly more accurate central-difference formulation [f(x+h)- f(x-h)]/2h. The default value is 1. Possible values are $1 \leq G r a d i e n P o i n t s \leq 5.0$ .
Use Central Differences	This parameter allows you to determine whether or not Isight will use the central difference method for calculating output derivatives. When this option is not selected, the forward difference method is used. Using this option increases the accuracy of the gradient calculations at the expense of double the number of design point evaluations.
Max Failed Runs	This parameter is used to set the maximum number of failed subflow evaluations that can be tolerated by the optimization technique. If the number of failed runs exceeds this value, the optimization component will terminate execution. To disable this feature, set this option to any negative value (e.g., –1). When this option is set to a negative value, the optimization will continue execution despite any number of failed subflow runs.
Failed Run Penalty Value	This parameter represents the value of the Penalty parameter that is used for all failed subflow runs. The default value is $1 \times 10^{30}$ .
Failed Run Objective Value	This parameter represents the value of the Objective parameter that is used for all failed subflow runs. The default value is $1 \times 10^{30}$ .
Save Technique Log	Most optimization techniques create a log file of information/messages as they run. This information can be useful for determining why an optimizer took the path that it did or why it converged. Some of these log files can get extremely large, so they are not stored with the run results by default. Select this option if you want to store the log with the run results (as a file parameter) for later viewing.

Click Update Component to save your changes.