Re: [Gnucap-devel] transient -- "trace" default

[al davis]

On Tuesday 07 January 2014, Felix Salfelder wrote:
> ELEMENT::tr_review_trunc_error seems to correctly implement
> the truncation error in case order() == 1. unless i'm
> missing something, it makes perfect sense to use it for step
> control.

No.

If you want an overly stable method with step control, use Gear.

The reason for using Euler is that sometimes you do want to 
ignore the error, otherwise strays will take control and it will 
run very slow.

v1 (1 0) pulse .....
r1 (1 2) 1meg
c1 (2 0) 1p

a simple low pass filter?  maybe.

but it's part of a power supply running at 60 Hz.  I want to 
ignore the 1pf capacitor, as if it didn't exist.  With Euler, 
that's what happens.  With trap, ignoring step control here 
would lead to a severe case of trap ringing.

Regardless, the voltage curve fit step control still applies, so 
the circuit does have some step control.