On Jul 11, 2011, at 7:25 PM, Thomas S. Dye wrote:
David Winsemius <dwinsem...@comcast.net> writes:
On Jul 11, 2011, at 3:28 PM, Thomas S. Dye wrote:
Aloha all,
I have an adjacency matrix for an acyclic digraph that contains
transitive relations, e.g. (u,v), (v,w), (u,w). I want a DAG with
only
intransitive relations. Can someone point me to an R function that
will
take my adjacency matrix and give me back one with only intransitive
relations? In the example, I'd like to get rid of (u,w) and keep
(u,v)
and (v,w).
I'm needing to guess at what sort of code you are using but assuming
this is a square matrix:
require(ggm)
dag <- DAG(y ~ x, x ~ z, u~z)
which(dag != t(dag), arr.ind=TRUE)
row col
x 2 1
y 1 2
z 3 2
x 2 3
u 4 3
z 3 4
Aloha David,
Thanks for this suggestion. I don't think it does what I want. Sorry
if I wasn't precise. The graph theory language is new to me.
It appears to me to be new as well. I imagined that w ~ u and u~w
would be the definition of "transitive" when directed was a modifier,
but apparently there are mathematical constructions that are more
complex than I imagined.
What I'm looking for is a function that gets rid of transitive
relations, like so:
tdye> dag <- DAG(v ~ u, w ~ v, w ~ u)
tdye> dag
v u w
v 0 0 1
u 1 0 1
w 0 0 0
tdye> dag[2,3] <- 0
tdye> dag
v u w
v 0 0 1
u 1 0 0
w 0 0 0
All the best,
Tom
All the best,
Tom
--
Thomas S. Dye
http://www.tsdye.com
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David Winsemius, MD
West Hartford, CT
--
Thomas S. Dye
http://www.tsdye.com
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
