[Torch5-devel] Memory leaks

[Clément F. <cle...@gm...>]

Hi all,

I also noticed some severe memory leaks (lack of garbage collection) on
tensor allocation.

Try to run:
> for i = 1,1000000 do a = torch.Tensor(500,500) end
(you can stop it before it consumes all your mem...)

at the end of this for loop, there's only one valid reference to a tensor,
but nothing ever gets garbage collected. Even a manual call to the garbage
collector doesn't clean that up.

Maybe I'm mistaken, and that kind of data cannot be handled by the garbage
collector ?
If it is so the work around is to always pre-allocate tensors, and only
resize/fill them with new data in loops, as you would do it in C... but that
sort of defeats the purpose of a scripting language right ?

Other (less important) leak, the function qt.QImage.fromTensor(tensor)
returns a freshly allocated QImage, that doesn't seem to be garbage
collectible. That basically makes QT displays have a limited lifetime :-(,
as any tensor needs to be converted like that first.
I've written an other function that fills a QImage passed as an argument, to
avoid this leak, but it would be better if the QImage was simply collected
at some point.

Clement.