Jiaming Yuan 5c2575535f
Fix Histogram allocation. (#4347)
* Fix Histogram allocation.

nidx_map is cleared after `Reset`, but histogram data size isn't changed hence
histogram recycling is used in later iterations.  After a reset(building new
tree), newly allocated node will start from 0, while recycling always choose
the node with smallest index, which happens to be our newly allocated node 0.
2019-04-10 19:21:26 +08:00
..
2018-10-01 01:29:03 +13:00
2019-03-13 02:25:51 +08:00
2019-04-10 19:21:26 +08:00
2019-03-13 02:25:51 +08:00
2016-12-04 11:25:57 -08:00