Re: Why recovering from broken configs is too hard

Alexander Viro
2001-05-03T08:30:32Z

On Thu, 3 May 2001, Eric S. Raymond wrote:

> The obvious thing to try is to start with the configuration you have
> and try mutating the variables that occur in the broken constraint(s).
> Of course, there are 3^n of these where n is the number of distinct
> variables, so this is going to blow up really fast; 3, 9, 27, 81, 243
> and we ain't even to six symbols yet. By the time we get to the
> twelve variables that could be linked by just *one* constraint, there
> are 531,441. Even if you can check 500 configurations a second it's
> going to take 16 minutes just to get a candidate list.
>
> But wait! There's more! If some of the variables participate
> in multiple constraints, the numbers get *really* large. Worst-case
> you wind up having to filter 3^1976 or

<DSW>
I see your 3^1976 and raise "unsolvable". It's a special case
of termination problem, dontcha see.
</DSW>

Yes, generic problem is damn hard. The thing being, _this_ problem is
damn far from generic.