I have to implement an algorithm to decompose 3D volumes in voxels. The algorithm starts by identifying which vertexes is on each side of the cut plan and in a second step which edge traverse the cutting plan.
This process could be optimized by using the benefit of sorted list. Identifying the split point is O log(n). But I have to maintain one such sorted list per axis and this for vertexes and edges. Since this is to be implemented to be used by GPU I also have some constrains on memory management (i.e. CUDA). Intrusive listsM/trees and C are imposed.
With a complete ‘voxelization’ I expect to endup with ~4000 points, and 12000 edges. Fortunately this can be optimized by using a smarter strategy to get rid of processed voxels and order residual volumes cutting to keep their number to a minimum. In this case I would expect to have less then 100 points and 300 edges. This makes the process more complex to manage but could end up beeing more efficient.
The question is thus to help me identify the criteria to determine when the benefit of using a sorted data structure is worth the effort and complexity overhead compared to simple intrusive linked lists.
The question will ALWAYS boil down to which operator is most common, accessing, or adding. If you have an unordered list, adding to it takes no time, and accessing particular items takes extra time. If you have a sorted list, adding to it takes more time, but accessing it is quicker.
Most applications spending most of their time accessing the data, rather than adding to it, which means that the (running) time overhead in creating a sorted list will usually be balanced or covered by the time saved in accessing the list. If there is a lot of churn in your data (which it doesn’t sound like there is) then maintaining a sorted list isn’t necessarily advisable, because you will be constantly resorting the list as considerable CPU cost.
The complexity of the data structures only matters if they cannot be sorted in a useful way. If they can be sorted, then you’ll have to go by the heuristic of
number of accesses:number of changes
to determine if sorting is a good idea.