Re: [jgrapht-users] Implement composition of graphs

[Victor P. <po...@na...>]

Let R and S be directed graphs.

I will denote xTy iff there is an edge from x to y (for digraph T).

Now I want to calculate the graph R*S defined by the formula:

x(R*S)z <=> exists y: (xSy and yRz)

It seems that this is not implemented in JGraphT.

It seems that I will implement this in near future (unless somebody
does it quicker than me ).

On Thu, 2017-12-28 at 12:19 -0500, J Kinable wrote:
> You need to be a bit more explicit as what you want/need. I have no
> idea what you mean by "composition of binary relations as digraph".
> There is no representation of "binary relations". Obviously, there
> are plenty of different digraphs and algorithms available. Many
> algorithms can be easily implemented using the building blocks that
> are already present in the library. 
> On Thu, Dec 28, 2017 at 8:55 AM, Victor Porton <po...@na...>
> wrote:
> > I need composition of digraphs (I mean composition of binary
> > relations
> > 
> > represented as digraphs.) in my project. It seems that JGraphT is
> > 
> > missing this operation.
> > 
> > 
> > 
> > Is it really missing?
> > 
> > 
> > 
> > If it is missing I want to implement it.
> > 
> > 
> > 
> > I remind that composition is defined by the formula
> > 
> > 
> > 
> > x(R*S)z <=> exists y: (xSy and yRz)
> > 
> > 
> > 
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