Active tile count

[Megidd]

Goal

There are situations in which there is curiosity to know how many active tiles are at each tree level. Hence, a new method is developed to return a vector containing active tiles at each level.

Note

This new method is developed by using bitmask counting which is faster than old technique of tree-iterator.

Unit and benchmark test

Unit test is developed by comparing this new method with the older tree-iterator method. Also, benchmark test can be done by using commented-out timer statements in unit test.

Notice

This PR is developed by closely following PR #536 steps.

[linux-foundation-easycla[bot]]

The committers are authorized under a signed CLA.

• :white_check_mark: Megidd (644f4ca33e347567297a6b3a85d21ed8b7145746, 58f7ab660df1dc8e4f2a440ea61f673c3ffc02ae, 98692d598f6f26be0f3ef494aa086ce268088dc1, d55c9f8badacd8257738deb2d2680202f633273d, feffebd45f22626b6a264042947196b8dfd71c5c, d458b3f938d45bdbfafacd066ef6d718f3467e8a, 17964260592c813886e9d980baca2dd7888e237d, 8ad8573fdb21044824f1aef223e2cfa41ab8a1c2, 871b1fffefe9af7874de9f948a2e6b95fe9877be, 82355b7d3b59fdb31f204f9c46541887f6c99fdb, be3772e22b5e0b942f46d0461a998fbc1ce6bcd6, 3eb414ae25dbb6e195019a190774f8fbdc25e2cb, dd596baac0a43428fd8fbf9686f059f0db678a79)

[Megidd]

... are you contributing this with a particular use case in mind?

Well, not specifically =) At times we are curious to know how many active tiles are at each level just to have more insight.