eldo_user

Optimization
Scaling Design Objectives
In these cases the objective statement parameters GOAL, EQUAL, LBOUND, UBOUND,
WEIGHT and TYPVAL must be a scalar value or a constant waveform. Refer to “Specifying
Design Objectives Using .OBJECTIVE” on page 608 for more details on these parameters.
When waveforms are used in OBJECTIVE_INFO, the value of the objectives (goal and bounds)
are sampled values of the waveform at simulation points.
It is possible to mix scalar values and waveforms. Specifying LBOUND as a scalar means that
this bound is global.
Related Topics
Implicit and Explicit Data Points
Scaling Design Objectives
Consider the scale of the design objectives, particularly in relation to the stopping conditions
and the computation of derivatives. Differing sizes among the component functions of an
extracted measure F can cause the same types of problems as differing sizes among the
optimization variables.
For instance, if the algorithm requires a decrease in the merit function, and it is clear that if the
units of two component functions of F(x) are widely different, then the smaller component
function is virtually ignored. For this reason, the Eldo optimizer algorithms also use a positive
diagonal scaling matrix Df on the design objectives F(x), which works as D does on x.
The diagonal matrix Df is chosen so that all the components of Df . F(x) will have a similar
magnitude. You can specify an initial Df using the parameter TYPVAL. The algorithm then
sets:
The result of this scaling procedure is described in the output file .otm, in the section headed
Section 1- Scaling Transformation Design Objectives. Refer to “ASCII Optimization File
Contents” on page 643 for more information.
Related Topics
Specifying Design Objectives Using .EXTRACT
Specifying Design Objectives Using .OBJECTIVE
Types of Design Objective
Design Objectives for Multi-Point Simulation
Eldo® User's Manual, 15.3 621