Re: [eigen] Indexes: why signed instead of unsigned?

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

There's a new thread on the forum about that (sigh).
http://forum.kde.org/viewtopic.php?f=74&t=87883

Let's settle this once and for all. There are 2 debates:
1) signed or unsigned?
2) int (that is 32 bits) or same-sizeof-as-pointers (e.g. 64bit on
64bit platforms)?

For 2) signed, we could do ptrdiff_t, i guess. Unless you're sure that
'long' is actually on all platforms the size of a pointer. I still
dont know whether 2) matters. Certainly not for cubic-complexity
algorithms (would take forever). But for plain "level 1" operations,
perhaps it's plausible. Feels like we shouldn't arbitrarily restrict
sizes to 32 bits. Opinions?

For 1), I don't know. the forum poster mentions a reasonable way to
write decreasing for loops. It's true that such loops are not too
frequent anyway. I dont know. Asking for opinions. Dont want to impose
upon you a decision made 3 years ago when I was a "noob".

Gael? Hauke? Jitse? Thomas? everybody?

Benoit