eldo_user

Optimization
Scaling Design Variables
* LCR Parallel Network
VIN 1 0 AC 10
R2 1 2 50
R3 2 3 50K
R5 3 0 50
L1 2 3 100U
C4 2 3 1N
VIN2 a 0 AC 10
RA A B 50
RB B C 50K
RC C 0 50
LA B C 100U
CA B C 1N
.PARAMOPT E(C4,C)=(1N,1N,20N)
.CORREL EXPR E(CA,C)=’1.2* E(C4,C)’
Note
The meaning of .CORREL EXPR is completely different to .CORREL in a Monte Carlo
analysis.
See Also
• .CORREL EXPR in the Eldo Reference Manual
• .PARAMOPT in the Eldo Reference Manual
Related Topics
Discretized Design Variables
Specifying Design Variables
Scaling Design Variables
Scaling Design Variables
This topic considers the effect of widely disparate variable scales on the algorithms and how to
deal with it. For example, you may have a minimization problem in which the first design
variable x (1) is in the range [10 8 , 10 9 ] Hz and the second x (2) in the range [10 −7 , 10 −6 ] seconds.
These ranges are referred to as the scales of the respective variables.
Scaling will affect algorithms when calculating the difference between iterates (the successive
values of design variables taken during optimization). In the above example the second variable
(time) is virtually ignored in any calculation.
The Eldo optimizer SQP method rescales the variables used in the optimization - that is,
changes their units. For example, if the units of x (1) are changed to gigahertz (GHz) and the
units of x (2) are changed to microseconds (μs), then both variables have the range [0.1, 1] and
Eldo® User's Manual, 15.3 599