That much is expected right? Since it stores a 4-byte index along with each 8-byte double value, the sparse representation is bigger when over 8/(4+8) = 66% of the values are non-default / non-zero.
But variable-encoding the index value trims a byte or more per element depending on your assumptions. It'll still be less efficient past a certain (higher) point though that's by design. But a byte per element adds up at huge scale, I still find this worth entertaining. On Sun, May 2, 2010 at 5:49 PM, Robin Anil <robin.a...@gmail.com> wrote: > PS, The size of the SparseVector is greater than the dense vector for a full > vector. I guess something could be done about it.