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To: AndrewC
Okay, when the program "displaying" the genetic algorithm terminates, describe the "solution". When does the genetic algorithm program terminate? Why does it terminate?

Define for me how much salt to add to 2 pounds of mashed potatoes. How much is the right amount? How do you know to stop adding salt? Is that amount of salt correct for GGG? For me? For everyone? Or only for you? Is that after or before addition of milk and butter, and what type of potatoes?

A GA is terminated (it doesn't end on its own) when the programmer/researcher decides he has an answer he can work with.

Imagine I give you a 30 element network to create a 20th order bandpass filter. You have unlimited choices of resistors, capacitors, and inductors to use. I want that filter to have a Chebychev response with a defined passband gain, passband ripple, and attenuation outside the passband.

Now, I also want you to make the filter as low cost as possible! However, since this is going on a research vessel, weight matters, as does size - we can't have a perfect fit filter that weighs more than 5 pounds, and occupies more than 200 cubic inches! And budgets being what they are, lower cost is always wanted.

In fact, if you can make it significantly smaller, we'd be willing to trade off some cost, or maybe some performance. If you can make it lighter, that's even better than small but not too much better. Light AND small together is really good - better than either one by themselves, or even together.

So how do you find the filter that best trades off functionality (the electrical passband/stopband performance) for cost, size, and weight? Each component you select has electrical, fiscal, and physical dimensions, and you have to solve for a solution that works.

There isn't just ONE solution here - given the complexity of the problem, there can be literally INFINITE valid solutions! But your problem is to figure out how to make one that YOU believe is pretty darn good.

THAT is how you use a GA. For solving problems where you have an idea of "how much salt is enough", but to exactly quantify it is essentially impossible and in fact irrelevant. You need a "good enough" answer that you - and your customer/boss - will be happy with.

70 posted on 05/09/2009 3:09:56 PM PDT by PugetSoundSoldier (Indignation over the sting of truth is the defense of the indefensible)
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To: PugetSoundSoldier
Define for me how much salt to add to 2 pounds of mashed potatoes. How much is the right amount? How do you know to stop adding salt? Is that amount of salt correct for GGG?

That is called cooking. It is definitely an intelligent process.

A GA is terminated (it doesn't end on its own) when the programmer/researcher decides he has an answer he can work with.

And how does he decide that? Flip a coin?

Imagine I give you a 30 element network to create a 20th order bandpass filter. You have unlimited choices of resistors, capacitors, and inductors to use. I want that filter to have a Chebychev response with a defined passband gain, passband ripple, and attenuation outside the passband. ...

...

But your problem is to figure out how to make one that YOU believe is pretty darn good.

Type I or type II?

You start here.

P.S. A bandpass filter is a filter that "attenuates" outside the passband.

P.P.S. There's a heck of a lot more information needed than what you provided. Power supplies, loads, temperature conditions, stability over time and or temp... etc.

75 posted on 05/09/2009 3:32:19 PM PDT by AndrewC (Metanoia)
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