I would appreciate any tips on how to extend the + operator in this
way, since I would like to implement Minkowski sums of polytopes and
this is natural notation for that.
Marshall
On Sep 25, 10:37 am, "Mike Hansen" <[EMAIL PROTECTED]> wrote:
> In SAGE, '+' is used for union of sets. For example,
>
> sage: a = Set([1,2])
> sage: b = Set([2,3])
> sage: a+b
> {1, 2, 3}
>
> Since currently, + is not defined for graphs, it'd be a natural choice.
>
> --Mike
>
> On 9/25/07, Jason Grout <[EMAIL PROTECTED]> wrote:
>
>
>
> > I'm thinking more about how to make the Graph class easy to use. One
> > thing that crops up is that the operations that combine graphs only
> > combine two graphs at a time (e.g., g.union(h), where g and h are graphs).
>
> > Is there a way to define an infix operator that would allow one to say:
>
> > g union h union i union j union k?
>
> > I could do it with something like:
>
> > reduce(lambda x,y: x.union(y), [g,h,i,j,k])
>
> > But that doesn't seem as clear as the infix things above.
>
> > For reference, Mathematica allows an operator in backticks to be applied
> > to its surrounding arguments, so the equivalent operation above would be:
>
> > g `union` h `union` i `union` j `union` k
>
> > And of course, you can set whether the operator is left-associative or
> > right-associative.
>
> > Of course, one solution is to use a for loop:
>
> > newgraph=Graph()
> > for graph in [g,h,i,j,k]:
> > newgraph.union(graph)
>
> > But that seems a lot clunkier than the infix expression above.
>
> > I guess another solution is to return the new graph from the union, so
> > that you could do:
>
> > g.union(h).union(i).union(j)
>
> > Thoughts?
>
> > -Jason
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