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1983-10-04
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OPTIMIZATION ....... Initiates the optimization proc-
ess. The user will be asked if
hard copies of intermedite re-
sults are desired, and the num-
ber of random moves that are to
be attempted.
There is also a hidden function Q which allows the user
to abort (quit) the optimization process prematurely. This
option can be exercised anytime that the optimization process
is taking place. However, it is not immediate. Certain house-
keeping functions must be performed by the program before re-
turning to the user.
C. SENSITIVITY ANALYSIS
The sensitivity analysis option enables the user to eval-
uate the degree to which the various optimization elements can
contribute to meeting the desired performance. This option
will allow the user to determine the overall merit of including
certain element parameters in the optimization list, possibly
reducing the number of elements to a minimum, and thereby de-
creasing the time required for the process to terminate. It
would, for instance, make little sense to include a capacitor
whose gradient is 10 or so, when all other entries have gradi-
ents in the 100's or better. The value of this option should
be obvious to those who have proir experience with optimization
routines. For those that don't, this will soon become apparent.
Sensitivity analysis is accomplished by making small
changes in the value of the various elements, and then compar-
ing the error function with that of the original network. The
gradient is an indication of the degree by which the error
function improves with this incremental change.
Objectives must be in memory before sensitivity analysis
can be accomplished. If none are present, the program will
request a file name and then proceed to the objectives editor
in normal fashion.
D. OPTIMIZATION: METHODS AND TECHNIQUES
When optimizing any given circuit, it is important that
the user understand that optimization is simply a method of
fine tuning a circuit on a theoretical basis, much as one would
tune a circuit at a workbench. Here, we are attempting to ar-
rive at as good a starting point as possible before actually
implementing the circuit in hardware.
It is therefore necessary that one begin the optimization
process with a fairly decent starting point. As was mentioned
earlier, assigning starting values from out of the blue is a
miserable way to begin, and may lead to a lot of wasted time.
One should always start with as good an approximation as is
possible. For instance, when designing a wideband amplifier,
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