3 ms·

While I agree that Z-order curves are simpler, but it's fast to calculate Hilbert curves on modern CPUs too. Just to self plug: https://github.com/leni536/fast

• m1el 9y ago
  But using the same set of instructions, z-order encoding and decoding is 8 instructions (5 if you exclude size conversion and return): zorder64_inv: movabsq $0x5555555555555555, %rax pextq %rax, %rcx, %rdx shrq %rcx pextq %rax, %rcx, %rcx shlq $32, %rcx movl %edx, %eax orq %rcx, %rax retq zorder64: movl %ecx, %eax movabsq $0x5555555555555555, %r8 pdepq %r8, %rax, %rcx movl %edx, %eax pdepq %r8, %rax, %rax addq %rax, %rax orq %rcx, %rax retq
  • leni536 9y ago
    Nice! Now I wonder when 36 vs 8 machine instructions become a bottleneck. I have seen applications of space-filling curves in quasi Monte Carlo integration, it could be potentially significant there.