[.igraph.vs slow if lot of objects exist

[Iakov Davydov]

[.igraph.vs uses the folowing code:
i <- eval(i, c(graph[[9]][[3]], adj=adj, nei=nei, from=from, to=to,
                   as.list(parent.frame())))

in case of huge environment this operations takes a lot of time. I am not R expert, but I suppose this is better:

i <- eval(i, c(graph[[9]][[3]], adj=adj, nei=nei, from=from, to=to,
                   envir=parent.frame()))

[Gábor Csárdi (gabor.csardi)]

Thanks, indeed! Fixed in revision #1590 (0.5-main) and #1785 (0.6-main).

[Gábor Csárdi (gabor.csardi)]

Oooops, this is not a good fix, I reopened the bug....

[Iakov Davydov (iakov-davydov)]

As I said before, I am not R expert… And now I see my error; it's obvious, sorry.
But eval seems to have two arguments: envir and enclos. And "envir is a (pair)list or a data frame. Specifies the enclosure, i.e., where R looks for objects not found in 'envir'"

So it seems that i <- eval(i, envir=c(graph[[9]][[3]], adj=adj, nei=nei, from=from, to=to), enclos=parent.frame()) should work.

I am sorry, can't test that right now. Could you please?

(The easy way is to test speed create some big array like a=rep(0, 100000000))

[Iakov Davydov (iakov-davydov)]

And by the way it seems that by default enclos is set to parent.frame().

> a=1
> e1=list(b=2)
> (function() {eval(expression(a+b))})()
Error in eval(expr, envir, enclos) : object 'b' not found
> (function() {eval(expression(a+b), e1)})()
[1] 3
> (function() {eval(expression(a+b), e1, NULL)})()
Error in eval(expr, envir, enclos) : object 'a' not found

So maybe we don't need parent.frame here at all?

[Gábor Csárdi (gabor.csardi)]

You're totally right, of course. I've fixed this, it works as it should have always. Thanks!

Fixed in revisions #1592 (0.5-main) and #1792 (0.6-main).

[Gábor Csárdi (gabor.csardi)]

The development of igraph has moved to github, so please do not comment on this bug here. You are of course welcome to comment on github, here:
https://github.com/igraph/igraph/issues/60