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Had to Rollback my Jaffar Unification (Was: unify_with_occurs_check/2 might have been fixed)

From Mild Shock <janburse@fastmail.fm>
Newsgroups comp.lang.prolog
Subject Had to Rollback my Jaffar Unification (Was: unify_with_occurs_check/2 might have been fixed)
Date 2025-09-25 01:59 +0200
Message-ID <10b20kk$1cu8$1@solani.org> (permalink)
References <107t0fi$6bgl$1@solani.org> <10ajo4u$k5kc$1@solani.org> <10b2038$1ce0$1@solani.org>

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Hi,

The facinating result was the Jaffar Unification
beats Scryer Prolog even on the target JavaScript.
Not to speak of the Java target, which also beat it.

But I rejected Jaffar Unification, because it
temporarily modifies my frozen terms, which might
impede some future program sharing across

premptive threads. So I rolled back Pointer based
Jaffar Unification, and went back to Map Based
Union Find. Overall the Map and a slightly bigger

stack incures a factor 3x slowdown. So for Java I get now:

/* Dogelog Player 2.1.1 for Java */

% ?- bench, bench, bench.
% [...]
% % Zeit 469 ms, GC 0 ms, Lips 42, Uhr 24.09.2025 20:00
% % Zeit 318 ms, GC 0 ms, Lips 62, Uhr 24.09.2025 20:00
% % Zeit 329 ms, GC 0 ms, Lips 60, Uhr 24.09.2025 20:00
% % Zeit 378 ms, GC 0 ms, Lips 52, Uhr 24.09.2025 20:00
% true.

% ?- bench2, bench2, bench2.
% [...]
% % Zeit 847 ms, GC 0 ms, Lips 23, Uhr 25.09.2025 01:04
% % Zeit 506 ms, GC 0 ms, Lips 39, Uhr 25.09.2025 01:04
% % Zeit 186 ms, GC 0 ms, Lips 118, Uhr 25.09.2025 01:04
% % Zeit 418 ms, GC 0 ms, Lips 35, Uhr 25.09.2025 01:04
% true.

In the binary predicates (bench) the factor 3x is pretty
much seen. But in the unary predicates (bench2) the
factor is much higher , something 10x - 20x. And JavaScript

doesn't help. But this might be the price to pay for
a "non-intrusive" algorithm. Another name I have for my
current take is "non-tainting" algorithms.

Should put a closer eye what could be done "non-intrusive",
or maybe device an algorithm that is a mixture of "non-
intrusive" and "intrucive".

Bye

Mild Shock schrieb:
> Hi,
> 
> Scryer Prologs unify_with_occurs_check/2 might have
> been fixed. I can now test the following:
> 
> /* Scryer Prolog 0.9.4-660 */
> 
> % ?- bench, bench, bench.
> % [...]
> %    % CPU time: 0.148s, 57 inferences
> %    % CPU time: 0.126s, 57 inferences
> %    % CPU time: 0.214s, 58 inferences
> %    % CPU time: 0.213s, 58 inferences
> %    true.
> 
> % ?- bench2, bench2, bench2.
> % [...]
> %    % CPU time: 0.036s, 58 inferences
> %    % CPU time: 0.042s, 58 inferences
> %    % CPU time: 0.018s, 59 inferences
> %    % CPU time: 0.096s, 56 inferences
> %    true.
> 
> This was the test case, it includes
> unify_with_occurs_check/2:
> 
> hydra(0, _) :- !.
> hydra(N, h(X, X)) :- N > 0, N0 is N-1, hydra(N0, X).
> 
> hydra(0, A, A) :- !.
> hydra(N, h(X, X), A) :- N > 0, N0 is N-1, hydra(N0, X, A).
> 
> bench :-
>     hydra(1048576, X), hydra(1048576, Y, Y),
>     time(X = Y),
>     time(unify_with_occurs_check(X, Y)),
>     time(X == Y),
>     time(compare(_, X, Y)), fail; true.
> 
> bench2 :-
>     hydra(1048576, X), hydra(1048576, Y, Y),
>     time(copy_term(X-Y,_)),
>     time(term_variables(X-Y,_)),
>     time(\+ ground(X-Y)),
>     time(acyclic_term(X-Y)),
>     fail; true.
> 
> Bye
> 
> Mild Shock schrieb:
>> Hi,
>>
>> Since some idiots blocked me on Scryer Prolog issues,
>> I raise the issue here. Basically uniy_with_occurs_check/2
>> probably does use a different implementation of unification
>>
>> than find for (=)/2. Because it doesn't scale, I find:
>>
>> /* Scryer Prolog */
>> ?- test3(25).
>>     % CPU time: 0.001s, 57 inferences
>>     true.
>>
>> ?- test4(25).
>>     % CPU time: 2.133s, 57 inferences
>>     true.
>>
>> Expectation would be that unify_with_occurs_check/2
>> does just scale like it does in SWI-Prolog. In
>> SWI-Prolog I find:
>>
>> /* SWI-Prolog 9.3.30 */
>> ?- test3(25).
>> % -1 inferences, 0.000 CPU in 0.000 seconds (0% CPU, Infinite Lips)
>> true.
>>
>> ?- test4(25).
>> % -1 inferences, 0.000 CPU in 0.000 seconds (0% CPU, Infinite Lips)
>> true.
>>
>> The test case was simply a hydra variant. Actually the
>> last hydra modification posted by @kuniaki, which I
>> am currently ticking along now:
>>
>> hydra(0, _) :- !.
>> hydra(N, h(X, X)):- N>0, N0 is N-1, hydra(N0, X).
>>
>> hydra(0, A, A) :- !.
>> hydra(N, h(X, X), A):- N>0, N0 is N-1, hydra(N0, X, A).
>>
>> test3(N) :- hydra(N, X), hydra(N, Y, Y),
>>     time(X = Y).
>>
>> test4(N) :- hydra(N, X), hydra(N, Y, Y),
>>     time(unify_with_occurs_check(X, Y)).
>>
>> But of course there is a cut (!) in the first rules.
>>
>> Mild Shock schrieb:
>>> Hi,
>>>
>>> WebPL is already outdated I guess. It doesn't
>>> show the versions of the other Prolog systems
>>> it is using. While I had these results for
>>>
>>> the primes example in the WebPL playground:
>>>
>>> /* Trealla Prolog WASM */
>>> (23568.9ms)
>>>
>>> When I run the example here:
>>>
>>> https://php.energy/trealla.html
>>>
>>> I get better results:
>>>
>>> /* trealla-js 0.27.1 */
>>>
>>> ?- time(test).
>>> % Time elapsed 9.907s, 11263917 Inferences, 1.137 MLips
>>>
>>> Bye
>>
> 

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Thread

WebPL is already outdated Mild Shock <janburse@fastmail.fm> - 2025-08-17 18:37 +0200
  Heap/Stack versus WAM resp. ZIP (Was: WebPL is already outdated) Mild Shock <janburse@fastmail.fm> - 2025-08-18 14:52 +0200
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      Smarter Partial Strings would use Program Sharing ['$append'/3] (Was: Trealla knows Program Sharing (PS) Tricks ?) Mild Shock <janburse@fastmail.fm> - 2025-08-18 15:42 +0200
        Static Shunting is even better [Dogelog Player] (Was: Smarter Partial Strings would use Program Sharing ['$append'/3]) Mild Shock <janburse@fastmail.fm> - 2025-08-18 15:49 +0200
  The Artificial Intelligence Flip: Acer Swift Go! (Was: WebPL is already outdated) Mild Shock <janburse@fastmail.fm> - 2025-08-31 23:56 +0200
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        AI soaked PCs: Is there a Copilot+ Prolog? (Was: AI means ambracing Non-Linearity) Mild Shock <janburse@fastmail.fm> - 2025-09-19 10:10 +0200
          The morning coffee incident [Prolog Community] (Was: AI soaked PCs: Is there a Copilot+ Prolog?) Mild Shock <janburse@fastmail.fm> - 2025-09-19 14:38 +0200
            Root Cause Prediction for Your Brain (Was: The morning coffee incident [Prolog Community]) Mild Shock <janburse@fastmail.fm> - 2025-09-19 18:22 +0200
              Please delete my account and all my posts on SWI-Prolog discourse (Re: Root Cause Prediction for Your Brain) Mild Shock <janburse@fastmail.fm> - 2025-09-19 18:38 +0200
                I will consult a Lawyer of mine (Was: Please delete my account and all my posts on SWI-Prolog discourse) Mild Shock <janburse@fastmail.fm> - 2025-09-19 18:42 +0200
  Scryer Prolog unify_with_occurs_check/2 doesn't scale (Was: WebPL is already outdated) Mild Shock <janburse@fastmail.fm> - 2025-09-19 16:08 +0200
    How bad is Rust, can JavaScript beat it? (Was: Scryer Prolog unify_with_occurs_check/2 doesn't scale) Mild Shock <janburse@fastmail.fm> - 2025-09-19 16:18 +0200
    unify_with_occurs_check/2 might have been fixed (Was: Scryer Prolog unify_with_occurs_check/2 doesn't scale) Mild Shock <janburse@fastmail.fm> - 2025-09-25 01:50 +0200
      Had to Rollback my Jaffar Unification (Was: unify_with_occurs_check/2 might have been fixed) Mild Shock <janburse@fastmail.fm> - 2025-09-25 01:59 +0200
        Trealla Prolog might apply "frozeness" to cyclic terms (Was: Had to Rollback my Jaffar Unification) Mild Shock <janburse@fastmail.fm> - 2025-09-25 02:06 +0200
          Non-intrusive through "frozen" subcategories (Was: Trealla Prolog might apply "frozeness" to cyclic terms) Mild Shock <janburse@fastmail.fm> - 2025-09-25 02:21 +0200
    Scryer Prolog occurs check cannot do hydra (Was: Scryer Prolog unify_with_occurs_check/2 doesn't scale) Mild Shock <janburse@fastmail.fm> - 2025-09-26 12:19 +0200
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  primes.pl mainly tests the Prolog ALU [mod/2 vs rem/2] (Was: WebPL is already outdated) Mild Shock <janburse@fastmail.fm> - 2025-10-15 02:38 +0200
    25-30% is insane, Neural Network Branch Prediction? (Was: primes.pl mainly tests the Prolog ALU) Mild Shock <janburse@fastmail.fm> - 2025-10-15 04:33 +0200
      NPUs (Neural Processing Units) are the new normal (Was: 25-30% is insane, Neural Network Branch Prediction?) Mild Shock <janburse@fastmail.fm> - 2025-10-15 16:04 +0200
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            Give Julio Di Egidio the bloody money [3 RMB¥ MiniMind] (Re: Eat Tteokbokki before SkyNet kills you [$100 ChatGPT]) Mild Shock <janburse@fastmail.fm> - 2025-10-18 16:19 +0200
              Vertex AI Training is more expensive? (Was: Give Julio Di Egidio the bloody money [3 RMB¥ MiniMind]) Mild Shock <janburse@fastmail.fm> - 2025-10-21 00:32 +0200
        The Love Affair: OpenAI and AMD (Was: NPUs (Neural Processing Units) are the new normal) Mild Shock <janburse@fastmail.fm> - 2025-10-18 18:59 +0200
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          Fuzzy Alert: Boris the Loris on the Dancefloor (Was: The NPU in your Browser [WebNN by W3C]) Mild Shock <janburse@fastmail.fm> - 2025-10-26 11:33 +0100

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