The isDense approach is slightly more future-proof since there might be more ways of being dense than just DenseVector. For instance, some math packages have special code for symmetric dense matrices that only store half the data, but are still best considered dense matrices. Other matrices like Toeplitz or Hilbert matrices or the random matrices that we use for random projection all have a relatively small amount of data that defines them, but every element is defined so they are best considered dense.
I wouldn't expect that we will need these special forms any time soon, but the term right-er probably applies. On Sun, Jan 23, 2011 at 2:56 AM, Sean Owen (JIRA) <[email protected]> wrote: > I think the right-er design would be an isDense() flag or something that > affects behavior within one method. However for now I was just committing > the patch. >
