Your approach is more compact than mine, which would be a significant
advantage for large collections.
Also, I'd discard the 0 value before grouping (since 0 here is an
artifact of the representation and not a part of the original data
set).
This gives:
OID=: 1 9 6 2 10 7 3 11 4
NID=: 2 10 7 3 11 12 4 8 5
G=: NID OID} i.1+>./NID,OID
(</. #\)}.{:@({&G^:a:"0)i.#G
+---------+------+---------+
|1 2 3 4 5|6 7 12|8 9 10 11|
+---------+------+---------+
Or, this could be sorted.
That said, note that this only works for tree structured graphs. Which
is probably always going to be the case here.
Thanks,
--
Raul
On Fri, Sep 3, 2021 at 12:53 PM Michal Wallace <michal.wall...@gmail.com> wrote:
>
> Oh, Raul's version using +. (or) on the connection matrix is way nicer than
> my version, and gets rid of my bug with directions. Do that instead. :)
>
> On Fri, Sep 3, 2021 at 12:31 PM Raul Miller <rauldmil...@gmail.com> wrote:
>
> > I should note that your example connection matrix does not seem to
> > match the oid, nid values you displayed.
> >
> > OID=: 1 9 6 2 10 7 3 11 4
> > NID=: 2 10 7 3 11 12 4 8 5
> >
> > Here's the connection matrix I see represented:
> > ]CM=: 1 (<:OID,.NID)} 0$~,~>./OID,NID
> > 0 1 0 0 0 0 0 0 0 0 0 0
> > 0 0 1 0 0 0 0 0 0 0 0 0
> > 0 0 0 1 0 0 0 0 0 0 0 0
> > 0 0 0 0 1 0 0 0 0 0 0 0
> > 0 0 0 0 0 0 0 0 0 0 0 0
> > 0 0 0 0 0 0 1 0 0 0 0 0
> > 0 0 0 0 0 0 0 0 0 0 0 1
> > 0 0 0 0 0 0 0 0 0 0 0 0
> > 0 0 0 0 0 0 0 0 0 1 0 0
> > 0 0 0 0 0 0 0 0 0 0 1 0
> > 0 0 0 0 0 0 0 1 0 0 0 0
> > 0 0 0 0 0 0 0 0 0 0 0 0
> >
> > Note that I am using a recent J version here. In older versions of J,
> > that would have to be 1 (<"1<:OID,.NID)} 0$~,~>./OID,NID
> >
> > Anyways, its transitive closure would be:
> > (+. +./ .*~)^:_ CM
> > 0 1 1 1 1 0 0 0 0 0 0 0
> > 0 0 1 1 1 0 0 0 0 0 0 0
> > 0 0 0 1 1 0 0 0 0 0 0 0
> > 0 0 0 0 1 0 0 0 0 0 0 0
> > 0 0 0 0 0 0 0 0 0 0 0 0
> > 0 0 0 0 0 0 1 0 0 0 0 1
> > 0 0 0 0 0 0 0 0 0 0 0 1
> > 0 0 0 0 0 0 0 0 0 0 0 0
> > 0 0 0 0 0 0 0 1 0 1 1 0
> > 0 0 0 0 0 0 0 1 0 0 1 0
> > 0 0 0 0 0 0 0 1 0 0 0 0
> > 0 0 0 0 0 0 0 0 0 0 0 0
> >
> > But that does not match your suggested grouping operation (foo), so
> > let's assume that connections work both ways:
> >
> > ]TC=: (+. +./ .*~)^:_ CM+.|:CM
> > 1 1 1 1 1 0 0 0 0 0 0 0
> > 1 1 1 1 1 0 0 0 0 0 0 0
> > 1 1 1 1 1 0 0 0 0 0 0 0
> > 1 1 1 1 1 0 0 0 0 0 0 0
> > 1 1 1 1 1 0 0 0 0 0 0 0
> > 0 0 0 0 0 1 1 0 0 0 0 1
> > 0 0 0 0 0 1 1 0 0 0 0 1
> > 0 0 0 0 0 0 0 1 1 1 1 0
> > 0 0 0 0 0 0 0 1 1 1 1 0
> > 0 0 0 0 0 0 0 1 1 1 1 0
> > 0 0 0 0 0 0 0 1 1 1 1 0
> > 0 0 0 0 0 1 1 0 0 0 0 1
> >
> > That gives us something close to the grouping you asked for:
> > TC </. 1+i.#TC
> > +---------+------+---------+
> > |1 2 3 4 5|6 7 12|8 9 10 11|
> > +---------+------+---------+
> >
> > The ordering here is different, but if that's important we could try to
> > fix it:
> >
> > (/: {:@>) TC </. 1+i.#TC
> > +---------+---------+------+
> > |1 2 3 4 5|8 9 10 11|6 7 12|
> > +---------+---------+------+
> >
> > I hope this helps,
> >
> >
> > --
> > Raul
> >
> > On Fri, Sep 3, 2021 at 11:21 AM Pablo Landherr <pablo.landh...@gmail.com>
> > wrote:
> > >
> > > I want to group items that are linked to each other. I tried to use some
> > > kind of connection matrix
> > >
> > > nid =/ oid NB. an example
> > >
> > > 0 0 0 1 0 0 0 0 0
> > >
> > > 0 0 0 0 1 0 0 0 0
> > >
> > > 0 0 0 0 0 1 0 0 0
> > >
> > > 0 0 0 0 0 0 1 0 0
> > >
> > > 0 0 0 0 0 0 0 1 0
> > >
> > > 0 0 0 0 0 0 0 0 0
> > >
> > > 0 0 0 0 0 0 0 0 1
> > >
> > > 0 0 0 0 0 0 0 0 0
> > >
> > > 0 0 0 0 0 0 0 0 0
> > >
> > >
> > > to group items linked to each other but I can't figure out how to proceed
> > > from there. I'm hoping someone has a trick in their toolbox to share with
> > > me.
> > >
> > > oid is the first number of all connections and nid is the second number.
> > So
> > > in this example 6 is connected to 7, 7 is connected to 12 and 12 has no
> > > further connection. What should foo be?
> > >
> > >
> > > oid,.nid
> > >
> > > 1 2
> > >
> > > 9 10
> > >
> > > 6 7
> > >
> > > 2 3
> > >
> > > 10 11
> > >
> > > 7 12
> > >
> > > 3 4
> > >
> > > 11 8
> > >
> > > 4 5
> > >
> > > oid foo nid
> > >
> > > ┌─────────┬─────────┬──────┐
> > >
> > > │1 2 3 4 5│9 10 11 8│6 7 12│
> > >
> > > └─────────┴─────────┴──────┘
> > >
> > >
> > > Thank you,
> > >
> > > Pablo
> > > ----------------------------------------------------------------------
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> >
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