Is the ACE algorithm for use with exact exchange, documented somewhere? I find in the code that the magic input variable userie 1729 deactivates ACE, and indeed, for a PBE0 calculation I find that this input slows down the calculation dramatically, although convergence seems to be to the same energy (but it segfaults at the end). So it appears that ACE is running by default, but is the behavior tunable in some way? I can find only very scarce documentation on doing hybrid calculations.