Re: gEDA-user: very backward time step?

[al davis <ad252@xxxxxxxxxxxxxxxx>]

On Tuesday 21 September 2010, Matthew Wilkins wrote:
> You're specifying a 10 ms step size (first parameter in the
> tran command), and  it looks like that's what you're
> getting.  The period of a 60 Hz sine wave is 16.6 ms, so
> you're getting fewer than 2 samples per cycle.  Try changing
> the step size to 1 ms and things should start to look
> better.

He's getting 1 second steps.

Spice only takes two numbers for transient.  He uses three, so 
it is Fortran order ..  start stop step.   The spice way of 
using a different order for each command confuses me, so Gnucap 
takes either spice order or Fortran order for everything.

Gnucap has the ability to continue a transient analysis, which 
spice doesn't, so some things need to change.


> In most simulations the solver would calculate additional
> intermediate time  steps which would show up with 'trace
> all', but I'm guessing that your circuit model is so simple
> and linear that the solver just calculated the values at the
> requested time steps without creating any intermediate
> points.

In 0.35, (and Spice) this is true.  In recent development 
versions, the step control is robust enough to figure this out 
regardless of what you specify.  (well almost, but yes in this 
case)


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