Internal helper, the three-dimensional analogue of
get_ArraySpeciesBySize_w(). Returns the geometric bin centres (see
bin_midpoints()) when the array is tagged as a bin average and the model
uses second-order bin-averaging, otherwise the grid nodes read from the size
dimension names. Falls back to the dimension names when no params is
attached.
get_ArrayTimeBySpeciesBySize_w(x)A numeric vector giving the size represented by each size slice.
An ArrayTimeBySpeciesBySize object.