faster blocked sampling
faster blocked sampling

davidkunio/dedupe,nmiranda/dedupe,neozhangthe1/dedupe,01-/dedupe,datamade/dedupe,pombredanne/dedupe,01-/dedupe,dedupeio/dedupe,tfmorris/dedupe,nmiranda/dedupe,neozhangthe1/dedupe,datamade/dedupe,davidkunio/dedupe,pombredanne/dedupe,dedupeio/dedupe,tfmorris/dedupe