My 4x4x4 optimal solver

[cuBerBruce]

I've built some pruning tables for BQTM, assuming I didn't make any programming errors.

U & D centers with respect to DLB corner:
dist  0: count =          1 total          1
dist  1: count =         12 total         13
dist  2: count =        217 total        230
dist  3: count =       4260 total       4490
dist  4: count =      64118 total      68608
dist  5: count =     779840 total     848448
dist  6: count =    6713546 total    7561994
dist  7: count =   26142524 total   33704518
dist  8: count =   17537779 total   51242297
dist  9: count =     240673 total   51482970

3x3x1 block:
dist  0: count =          1 total          1
dist  1: count =         12 total         13
dist  2: count =        234 total        247
dist  3: count =       4330 total       4577
dist  4: count =      76535 total      81112
dist  5: count =    1285915 total    1367027
dist  6: count =   18429091 total   19796118
dist  7: count =  191970261 total  211766379
dist  8: count = 1040548531 total 1252314910
dist  9: count = 1355916695 total 2608231605
dist 10: count =  101642625 total 2709874230
dist 11: count =      10794 total 2709885024

My favorite is still this one:

http://alg.garron.us/?cube=4x4x4¬at...Lw+Uw'+Lw2'+Bw'+r'+Bw+Rw'+R'+u+y'+M'+Uw+x2+z'

I don't care if I find a 13-ply shortcut, I'll still execute the algo above

Rest assured, there is no 13-move shortcut for the single dedge flip, not even in block turn metric. I think I had determined there is no 13-move reduction-state OLL parity fix that doesn't change the position of at least 4 dedges (not to mention corner effects). I think Clément has claimed 15 turns is the minimal dedge flip, but I'm not sure offhand if that has been proved and for what metrics.