This prints something like
% 4,623,232 inferences, 1.223 CPU in 1.229 seconds (99% CPU, 3780625 Lips)
But why aren't those values returned in variables?!?
They can't even be caught using
?- with_output_to(string(S),time(sleep(1))). % 1 inferences, 0.000 CPU in 1.000 seconds (0% CPU, 24841 Lips) S = "".
Time to go take a look at that code...
(Also, what exactly is a "logical inference" ... is it a clause call? LIPS seems to go back to marketing efforts made in the 80s during the 5th Generation project, it sounds a bit too high-level for Prolog.)