Does Diamond use a flattener in 1v1? I haven't seen any mention of one.
Yep, it does. In spirit, the decision criteria and configuration are similar to Dookious. Maybe the biggest implementation difference, besides VCS vs DC, is that Diamond has a more sophisticated system to decide when to enable it. Dookious has "tiers" - like never enable it in first few rounds, then hit % threshold is 9% until round 10, 10% until round 20, etc. Diamond just uses a single hit % + a margin of error based on how much data he's collected, similar to an election polling formula.
If you want to check out the code, see "initSurfViews()" in voidious/move/MoveEnemy.java. The last 3 are for the flattener. A "view" is a kd-tree + all associated configuration data, like parameters to decide on k, max data points, decay rate, and hit % threshold before it's enabled.
see Flattener. Instead of moving to the places with the least amount of danger, move to the places you have been less often. Ofcourse depending on your configuration and segmentation. In case of a wavesurfer, recording every fired bullet instead of only the times the enemy really hit you, would result in a 'flat' movement => flattener. The biggest problem with a flattener is the decision when to switch to the flattener and when not. (pro tip: search the wiki for info)