Why the size of descriptor is 256 float ?

[lijianglong2018]

Thank you for your great work!
I wonder why the size of the descriptor is 256 float? Have you tested the other size ?

Thanks in advance! Really hope to get your reply!

[ddetone]

We chose a large descriptor size to maximize the performance, though we also tested smaller descriptor sizes and saw good performance even down to 32 bytes.