Hans Dembinski

add hexagonal binning

1

add a 2d axis which does hexagonal binning Everything about hexagonal grids: https://www.redblobgames.com/grids/hexagons/

All accumulators support addition and scaling (multiplication by a constant). Additionally, we could support subtraction, multiplication, and division. Subtraction - [ ] count - [ ] sum - [ ]...

Unsafe access to accumulator data

5

- [ ] Test this with downstream boost-histogram

```c++ // c++17 auto h = bh::make_histogram(bh::axis::integer(0, 1), bh::dense_storage()); ``` This does not work (and currently shouldn't!) but fails in mysterious ways that are difficult to comprehend. If possible, we...

Add collector accumulator

1

A simple accumulator that just fills a `std::vector` with the samples passed to it. The user can then run any kind of statistical estimation on the sample. It is a...

Support `boost::rational` as value type for `axis::regular`

2

```cpp #include #include namespace bh = boost::histogram; int main() { using R = bh::axis::regular; auto h = bh::make_histogram(R(10, 0, 1)); } ``` This currently triggers a static_assert, but should be...

While we cannot avoid round-off error in the `index` and `value` methods of the `regular` axis, we want these two to be exact inverses of each other. In other words,...

Add pick command for reduce

4

Copied from #267: scikit-hep/boost-histogram#296 suggests that one should be able to pick individual bin indices from a category axis. The suggested command is `pick(index1, index2, ...)`, as suggested by @henryiii...

add Function transform

2

Henry has demonstrated in boost-histogram (the python module) that fast transforms can be generated also with a less static approach, where the transform stores two function pointers and uses that...

Replace axis::traits with uniform wrapper

1

Perhaps histogram could wrap external classes with an interface class that supplements all optional interface. If this works, it would greatly simplify the library compared to the current approach with...