On Saturday 24 April 2010, Link wrote: > I hadn't intended for anyone to interpret it that way, and > I'm sorry if you interpreted that as bashing gEDA. Perhaps > my choice of words was rather unfortunate.
Apology accepted. > What I intended to is that one component (the simulator) of > LTSpice tends to perform better _for me_ than gEDA's > equivalents, in sheer terms of the simulation results being > what I expect. I'm not sure if that is even a problem with > gnucap/ngspice or if I'm simply doing something wrong > myself, but I do know that I find LTSpice easier to use for > simulation. That does not mean I dislike gEDA, or think it's > bad, or anything of the sort - in fact, I find it to be > absolutely brilliant for schematic capture and PCB design. There is a real problem with the way "gnetlist" works. (contrary to what some others here say). I have known this for years. Often people have trouble with it. I don't know what to say. It seems I always need to hack the netlist. I have tried to recruit help on this, specifically making gschem and pcb plugins for the gnucap translator system. No takers. Maybe when I get my other pile of work out of the way I will do it myself, for both geda and kicad. Then "gspiceui" doesn't help. I don't like that style anyway. For a beginner, combined with how gnetlist works, I don't know what to do. In this environment, it's not gnucap or ngspice that is the trouble spot. It's gnetlist, documentation, and communication between tools. So the situation here is that people don't see the capability that ngspice and gnucap have because of problems elsewhere. The other problem people run into is that nobody here has collected the hundreds (thousands?) of models (of all kinds) that come from all over. A commercial organization can pay a junior person full time to maintain the collection. That's what it takes. Not in a commercial environment, this kind of thing has to be done by the community, a shared effort. But really "google for it", and "check to see if it makes sense" is the correct answer. A lot of those models don't make sense for the particular application people are asking about. The big collection that LT and P spice have, that is still incomplete because it is impossible to be truly complete, lulls users into a false confidence. As far as simulation results go .. If it gives you trouble, please report it. I'm well aware of the Spice3f5 false convergence issue, and that it still exists in NGspice. I'm well aware of the NGspice step control bugs, where an attempt to fix 3f5 problems really made it worse. I am not convinced that LTspice is any better in these issues than NGspice. As far as I know, Gnucap doesn't have these problems. Convergence and step control are never perfect. It seems to work for me, but if it doesn't for you, the only way it can get better is if you let me know about the problem, and send a test case that demonstrates it. The benchmarks I have tend to show that Gnucap usually outperforms NGspice on difficult circuits, and that LTspice usually performed about the same as NGspice. NGspice is often faster than Gnucap on small circuits, where both are fast enough that it doesn't really matter. The last time I made any of these comparisons was a few years ago, so some things might have changed. Gnucap has improved, perhaps LTspice has improved too. NGspice hasn't really changed in this regard. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user