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Simulators >> Circuit Simulators >> Generate Initial Guess for DC Solver Failed
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Message started by qiushidaren on Jun 18^th, 2007, 5:57pm

Title: Generate Initial Guess for DC Solver Failed
Post by qiushidaren on Jun 18^th, 2007, 5:57pm

Hi all,

When I do DC analysis using Analog Artist, I always meet such sentences like this:
*********************
DC Analysis ‘dc0p’
*********************
Attempt to generate initial guess for DC solver failed.

What is going on here, how can I solve this kind of problem, or it is not a problem or something?

Rgds,
Terry

Title: Re: Generate Initial Guess for DC Solver Failed
Post by Geoffrey_Coram on Jun 19^th, 2007, 10:35am

It's not a huge problem, as long as Spectre does eventually find a solution ... it might be taking longer than it should to find that solution.

I think Spectre tries to make a "good" initial guess for DC Newton -- a "dumb" initial guess would be: all nodes are zero, except those that have voltage sources on them. One could attempt to improve upon this by using some heuristics to guess some other values: if you know the voltage on one side of a diode, then the voltage on the other side might be 0.6V higher. I think the message is saying that Spectre's heuristics are having trouble with your circuit topology or some of the device models.