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Simulators >> Circuit Simulators >> Optimization Time
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Message started by aamar on Sep 8^th, 2005, 4:21am

Title: Optimization Time
Post by aamar on Sep 8^th, 2005, 4:21am

Dear Sirs,
I am using at the moment Neocircuit to optimize some simple analog blocks.

I define some goals which may be sometimes 4 to 6 goals with 4 to 5 parameters which is also not so wide and the step is almost not so large for example, 1 to 30 with step of 1.

I notice that the progress is so slow, sometimes all the goals are satisfied but still the progress bar shows only 4%. and some times, it doesn't achieve the goals even after 30% which takes about more than 12 hours trials.

I am using Spectre as simulator and define my goals using neocalc.

My questions are:
1. What is the meaning of achieving all the goals and still the progress is far from 100%, what is he doing more?
2. Is there any criteria to optimize or minimize the optimization time?,i.e. defining my goals in a special order, or special form?

Thanks in advance,

Best Regards.

aamar

Title: Re: Optimization Time
Post by Geoffrey_Coram on Sep 8^th, 2005, 8:28am

What do you mean by "achieving all the goals"?

Usually, an optimization has constraints which MUST be met (phase margin > 45), along with some goals (minimize power). Presumably, you have found a solution that satisfies all the constraints, but the optimizer still has a lot of the design space to explore to verify that the goals are truly optimized.

I don't know what you would mean by "achieving" a goal of "minimizing power" (well, OK, if you got zero power, then you could know there was nothing further to be done there).