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Experimental aggregate_by/4 was dismissed (Was: India & France had their AI Bikini Moment)

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I was exploring group_by/4 respectively a new
aggregate_by/4 for some machine learning statistics.
But the slowdown is not that aggravated if the extra
parameter _H is ground. The cost is smaller

factor then. So I had a change of mind in favor
of more declarative aggregate/3. Too much new predicates
isn't healthy so I dismissed the idea of supporting
distinct/2, group_by/4 and a new aggregate_by/4.

But somehow I fell in love with the idea of a new
firstof/2 predicate, instead of distinct/2, it could
be bootstrapped as follows:
```
firstof(X, Q) :-
    bagof(X, Q, L),
    L = [X|_].
```
Except it can be implemented like distinct/2 more
eagerly fitting to some other predicates from
the library(sequence):
```
p(1,a).
p(1,b).
p(2,c).
p(2,d).
p(2,e).

?- firstof(Y,p(X,Y)).
Y = a, X = 1;
Y = c, X = 2;
fail.
```

Mild Shock schrieb:
> Just noticed that group_by/4 calculates variables
> and then delegates to bagof/3. But the later predicate
> calculates also varables, so I suspect quite an overhead:
> 
> /* SWI-Prolog 9.3.19 */
> group_by(By, Template, Goal, Bag) :-
>      ordered_term_variables(Goal, GVars),
>      ordered_term_variables(By+Template, UVars),
>      ord_subtract(GVars, UVars, ExVars),
>      bagof(Template, ExVars^Goal, Bag).
> 
> I went with another soluton. First I provided a variant
> of aggregate/3 by the name aggregate_by/4 where one can
> offload the internal term_variables/2 calculation.
> Then use this bootstrapping:
> 
> /* Dogelog Player 1.3.0 */
> group_by(Witness, Template, Goal, List) :-
>     aggregate_by(Witness, bag(Template), Goal, List).
> 
> Here is some testing:
> 
> /* SWI-Prolog 9.3.19 */
> ?- length(_H,4000), time((between(1,2000,_),
>          group_by(X,Y,(nonvar(_H),between(1,10,Y),between(1,10,X)),L),
>          fail; true)).
> % 1,153,998 inferences, 0.562 CPU in 0.568 seconds (99% CPU, 2051552 Lips)
> true.
> ?- length(_H,8000), time((between(1,2000,_),
>          group_by(X,Y,(nonvar(_H),between(1,10,Y),between(1,10,X)),L),
>          fail; true)).
> % 1,153,998 inferences, 1.047 CPU in 1.060 seconds (99% CPU, 1102326 Lips)
> true.
> 
> /* Dogelog Player 1.3.0 */
> ?- length(_H,4000), time((between(1,2000,_),
>          group_by(X,Y,(nonvar(_H),between(1,10,Y),between(1,10,X)),L),
>          fail; true)).
> % Zeit 399 ms, GC 0 ms, Lips 16987636, Uhr 10.02.2025 10:49
> true.
> ?- length(_H,8000), time((between(1,2000,_),
>          group_by(X,Y,(nonvar(_H),between(1,10,Y),between(1,10,X)),L),
>          fail; true)).
> % Zeit 400 ms, GC 1 ms, Lips 16945167, Uhr 10.02.2025 10:50
> true.
> 
> The old version suffers from some term_variables/2
> dependency whereas the new version is totally immune
> on the size of the given goal, since any internal
> term_variables/2 has been offloaded.
> 
> I couldn’t name aggregate_by/4 as aggregate/4, since
> the later already exists in SWI-Prolog and SICStus Prolog
> and has a different semantics, it is not the analog of
> distinct/2, where one can specify Witnesses.
> 
> Mild Shock schrieb:
>> Hi,
>>
>> India & France had their AI Bikini Moment.
>> Facinating behavior:
>>
>> Macron Says He And PM Modi Will Push
>> https://www.youtube.com/watch?v=LwCK8yAnlkA
>>
>> But don't be fooled, things are possibly
>> more connected:
>>
>> Synthesia: France's 109-billion-euro AI investment
>> https://www.youtube.com/watch?v=_uyo4RG0Q6I
>>
>> Bye
>>
>>
>> Mild Shock schrieb:
>>> Hi,
>>>
>>> Suddently I got an allergy to name a predicate
>>> distinct/2. It is not so obvious that distinct/1 and
>>> distinct/2 are related. There is no constant C such that:
>>>
>>> distinct(X) :- distinct(C, X).
>>>
>>> Just joking, but for some consistency with the introduction
>>> of group_by/4 and aggregate_by/4 I went for the
>>> name first_by/2. The name is more intuitive:
>>>
>>> ?- [user].
>>> p(1,a).
>>> p(1,b).
>>> p(2,c).
>>> p(2,d).
>>> p(2,e).
>>> ^Z
>>> true.
>>>
>>> Now some queries:
>>>
>>> ?- p(X,Y), write(X-Y), nl, fail; true.
>>> 1-a
>>> 1-b
>>> 2-c
>>> 2-d
>>> 2-e
>>> true.
>>>
>>> ?- first_by(X, p(X,Y)), write(X-Y), nl, fail; true.
>>> 1-a
>>> 2-c
>>> true.
>>>
>>> Cool! The name is also used here with the same semantics:
>>>
>>> https://deephaven.io/core/docs/reference/table-operations/group-and-aggregate/firstBy/ 
>>>
>>>
>>
> 

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Deephaven inspired me to name a predicate [first_by/2] Mild Shock <janburse@fastmail.fm> - 2025-02-10 18:44 +0100
  India & France had their AI Bikini Moment (Was: Deephaven inspired me to name a predicate [first_by/2]) Mild Shock <janburse@fastmail.fm> - 2025-02-10 21:17 +0100
    More about an experimental aggregate_by/4 (Was: India & France had their AI Bikini Moment) Mild Shock <janburse@fastmail.fm> - 2025-02-16 12:24 +0100
      Experimental aggregate_by/4 was dismissed (Was: India & France had their AI Bikini Moment) Mild Shock <janburse@fastmail.fm> - 2025-02-16 12:25 +0100
        Re: Experimental aggregate_by/4 was dismissed (Was: India & France had their AI Bikini Moment) olcott <NoOne@NoWhere.com> - 2025-02-16 12:54 -0600

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