Unify system statistics determined by Key with Value. The
possible keys are given in the table .
Table: Keys for statistics/2
statistics
Display a table of system statistics on the current output stream.
time( +Goal)
Execute Goal just like once/1 (i.e. leaving no choice points),
but print used time, number of logical inferences and the average
number of lips (logical inferences per second). Note that
SWI-Prolog counts the actual executed number of inferences rather than
the number of passes through the call- and redo ports of the
theoretical 4-port model.
.
