The problem is that for arrays, most non-trivial datastructures have a high cost because of indirection. Memory is already the main bottleneck in many numerical

The problem is that for arrays, most non-trivial datastructures have a high cost because of indirection. Memory is already the main bottleneck in many numerical operations, and adding pointers is often terrible for memory performance. For arrays, even large, reasoning in terms of O(N) for access patterns is useless, because the constants are what matters.