Re: How I got rid of term_variables/3 (Was: 50 Years of Prolog Nonsense)

But we can also do without term_variables/3 or
term_variable/2.  don’ have tries in my system.
But I recently introduced Okasaki tree, but it
turned out that they are totally useless. What
works better in my case was hash+keysort, as
strange as it may sound.
I believe it depends on the grouping factor.
If there is a high grouping factor there is
higher precentage of read from the grouping
datastructure and than write into the
grouping datastructure. So if read is only O(1)
as in hash, you have better preformance than if
read is O(log N) as in tree. And you can also
afford a later keysort. Here is the bagof/3 choker
with hash+keysort compared to tree:
/* Dogelog Player 1.2.5, tree */
?- time(test3).
% Zeit 6073 ms, GC 1 ms, Lips 5182931, Uhr 10.11.2024 00:58
true.
/* Dogelog Player 1.2.5, hash+keysort */
?- time(test4).
% Zeit 3070 ms, GC 2 ms, Lips 9808736, Uhr 10.11.2024 00:58
true.
Quite amazing, if we compare to the traditional bagof/3:
/* Trealla Prolog 2.59.17, keysort */
?- time(test).
% Time elapsed 13.280s, 16158649 Inferences, 1.217 MLips
    true.
Mild Shock schrieb:

It all began with the bagof/3 choker:
 test :-
    bagof(X, N^(between(1,300,X), between(1,300,N),
       length(_,N)), _), fail; true.
 Which makes Prolog system tumble:
 /* SWI-Prolog 9.3.14 */
?- time(test).
Action (h for help) ? abort
% 468,739 inferences, 52.016 CPU in 53.069 seconds (98% CPU, 9012 Lips)
Execution Aborted
 /* Scryer Prolog 0.9.4-201 */
?- time(test).
^C   % CPU time: 110.153s, 145_508_466 inferences
    error('$interrupt_thrown',repl/0).
 Its mostlikely the same old problem that was
observed years ago, in that the canonicalization
of variables before the keysort/2 creates long
 instantiation chains. It can be solved by adjusting
the unification order. Here is a take in Dogelog Player:
 /* Dogelog Player 1.2.5 */
?- time(test).
% Zeit 7405 ms, GC 21 ms, Lips 3962971, Uhr 10.11.2024 00:57
true.