Your reasoning differs from the usual understanding of a null product (1
or True), as compared to a null sum (0 or False):
> the list of nodes for which
> *any path* from source to x must touch, i.e., the list of dominators
> of x.
Here, "any path" means all paths, a logical conjunction:
and [True, True] = True
and [True ] = True
and [ ] = True
The empty case of all sources touching is True, so 12 is a valid
dominator for 20 if there is no path from 12 to 20.
Dan
Denis Bueno wrote:
On Thu, Apr 17, 2008 at 11:32 AM, Denis Bueno <[EMAIL PROTECTED]> wrote:
On Wed, Apr 16, 2008 at 2:33 PM, Bertram Felgenhauer
<[EMAIL PROTECTED]> wrote:
> No. Data.Graph.Inductive.Query.Dominators is just buggy.
I have one more problem. For the attached graph, the dominators of
the -20 node are computed correctly (namely, [-20,-1,11,12]). But the
list of dominators for 20 is present, when in fact 20 isn't reachable
from 12. I think 20 should be absent from the return value of `dom
graph 12'. (And hence a call to `lookup 20 (dom graph 12)' should
return Nothing.) Instead it returns [-20,-1,-3,11,12,-14,17].
Is my reasoning correct? I'd try to fix the code, but, I don't
understand how it works.
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