After inserting nominal design parameters in the workflow editor, its options have to be set up for running the optimization. Select the item of the nominal parameter in the explorer to edit its options in the property window. The name, unit and comment can be changed. As the alternative for editing of a large number of nominal design parameters, the nominal editor can be used.
Value
This is a nominal value of the design parameter. for the optimization process, the value is used as start value for searching optimal point.
Start Step
This item will be only visible if the option "Start Step= Manual" is used in the optimization settings. If the option is set to "Standard", the start step for each design parameter is automatically set to 1/1000 of the defined search range by the Hooke-Jeeves-method or to 1/100 by the evolutionary algorithms.
Lower Boundary
Lower boundary is the most small value of the design parameter, which can be accepted by a optimization process:
Nominal Value ≥ Lower Boundary
At the optimization process, the value of the design parameter can violate the lower boundary. In this case, a penalty function will be created and handled with the highest priority to constrain the search process into the defined range. The simulation will be not performed to save time, because the point is not valid for design evaluation. If there is no lower boundary for this design parameter, set the value of the lower boundary to an extreme value (e.g. -1E100), which can be never reached by an optimization.
Upper Boundary
Upper boundary is the largest value of the design parameter, which can be accepted by the optimization process:
Nominal Value ≤ Upper Boundary
At the optimization process, the value of the design parameter can violate the upper boundary. In this case, a penalty function will be created and handled with the highest priority to constrain the search process into the defined range. The simulation will be not performed to save time, because the point is not valid for design evaluation. If there is no lower boundary for this design parameter, set the value of the upper boundary to an extreme value (e.g. 1E100), which can be never reached by an optimization.
Accuracy
For the optimization, it is sometimes necessary to limit the accuracy of the design parameters satisfy the design requirements. The accuracy is the smallest changing value of the design parameter, which can be set at an optimization process. The optimization step is a multiple of the accuracy. The accuracy must be positive or zero. If zero, the optimization variable may be a arbitrary real value. E.g.
Accuracy = 0 -> design parameter = arbitrary real value
Accuracy = 1 -> design parameter = integer value
Accuracy = 0.2 -> design parameter = a multiple of 0.2 (increment = 0.2)
Type
It supports four types for the nominal design parameter:
Constant
The nominal parameter is fix value for the entire optimization process. It cannot be changed
Variable
The nominal parameter is a optimization variable, which may have a arbitrary real value and can be changed by the optimization method. The changing increment is given by the option "Accuracy"
The value for the nominal parameter is a discrete value and label from the values list, which can be input by user.
Binary
The value of the nominal parameter represents binary number (0 or 1). The real value is defined by a number of bits. e.g. if the number of bits is 4, the code and decode of the nominal value will be defined as following:
0101 == 0*20 + 1*21 + 0*22 + 1*23 = 10