class TNDArrayRef<ULong64_t>

TNDArray

N-Dim array class.

Storage layout:
Assume 3 dimensions, array sizes 2, 4 and 3 i.e. 24 bins:
Data is stored as [0,0,0], [0,0,1], [0,0,2], [0,1,0],...

fSizes stores the combined size of each bin in a dimension, i.e. in
above example it would contain 24, 12, 3, 1.

Storage is allocated lazily, only when data is written to the array.

TNDArrayRef gives access to a sub-dimension, e.g. arr[0][1] in above
three-dimensional example, up to an element with conversion operator
to double: double value = arr[0][1][2];