On Fri, Jul 18, 2014 at 12:42 PM, Pat Ferrel <[email protected]> wrote:
> 2) I’m talking about the R semantics for rbind. Out of the box R is only > dense so the semantics by definition are dense. Putting in all zero rows > adds a bunch of 0.0 doubles to a matrix. I’m saying you don’t even need or > want the empty row keys. This is certainly not what we want in a sparse > vector or matrix unless needed. Please rely on Dmitriy, Sebastian, or Ted > about this and maybe they can contradict me. > I think that slavish adherence to core R semantics here is not intended or desirable. Rbind is a function that returns a new object which has the same effect as the dense copying, but could quite reasonably cheat for sparse objects. > > 3) If I did an rbind do you want me to overload it to take an Int and only > touch _nrow (not even sure this is possible—haven’t looked)? Is this really > what you want? > rbind should construct a new object. Since RDD's are immutable, it is OK to share structure (I think).
