[R] Add transitivity to a matrix?

Richard O'Keefe r@oknz @end|ng |rom gm@||@com
Tue Jun 18 02:12:44 CEST 2019

You have: a square logical matrix M representing a binary relation.
You want: a similar matrix representing the least (fewest true cases)
transitive relation extending what M represents.
It sound as though you are looking for the TRANSITIVE CLOSURE.
You will find that in the 'relations' package.

On Tue, 18 Jun 2019 at 05:39, Duncan Murdoch <murdoch.duncan using gmail.com>

> Suppose I have a square logical matrix M which I'm thinking of as a
> relation between the row/column numbers.
> I can make it into a symmetric relation (i.e. M[i,j] being TRUE implies
> M[j,i] is TRUE) by the calculation
> M <- M | t(M)
> Is there a simple way to ensure transitivity, i.e. M[i,j] & M[j,k] both
> being TRUE implies M[i,k] is TRUE?
> The operation should only change FALSE or NA values to TRUE values; TRUE
> values should never be changed.
> Duncan Murdoch
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