Logtalk 2.21.3 files.

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1164 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/examples/benchmarks/benchmark.pl

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+
+% benchmark a goal using a default number of repetitions and printing some 
+% useful statistics
+
+benchmark(Goal) :-
+	N = 10000000,
+	write('Number of repetitions: '), write(N), nl,
+	'$lgt_cpu_time'(Seconds1),		% defined in the config files
+	benchmark(N, Goal),
+	'$lgt_cpu_time'(Seconds2),
+	Average is (Seconds2 - Seconds1)/N,
+	write('Average time per call: '), write(Average), write(' seconds'), nl,
+	Speed is 1.0/Average,
+	write('Number of calls per second: '), write(Speed), nl.
+
+
+% repeat a goal N times using a failure-driven loop to avoid the interference 
+% of Prolog compiler memory management mechanism (such as garbage collection) 
+% on the results
+
+benchmark(N, Goal) :-
+	repeat(N),		% another option would be to use a between/3 built-in predicate
+		call(Goal),
+	fail.
+
+benchmark(_, _).
+
+
+% some Prolog compilers define the predicate repeat/1 as a built-in predicate;
+% if that's the case of the Prolog compiler you are using, then comment out 
+% the definition that follows
+
+repeat(0) :-
+	!.
+
+repeat(N) :-
+	N2 is N - 1,
+	repeat(N2).