# Cplint/pita forall / findall bug **URL:** \ **Category:** Pack\ **Tags:** bug\ **Created:** [March 30, 2022, 8:27am UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189 "2022-03-30T08:27:08Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [March 30, 2022, 8:27am UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/1 "2022-03-30T08:27:08Z")
```prolog :- use_module( library( pita)). :- pita. :- begin_lpad. a. b :- forall(prob( a, _), true). % don't work c :- findall(1, prob( a, _), _). % don't work d :- prob( a, _). % works e :- forall(true, true). % works f :- findall(1, true, _). % works :- end_lpad. /* (ins)?- prob(b,P). P = 0.0. % wrong (cmd)?- prob(c,P). P = 0.0. % wrong (ins)?- prob(d,P). P = 1.0. % ok (cmd)?- prob(e,P). P = 1.0. % ok (ins)?- prob(f,P). P = 1.0. % ok */ Regards ``` ---
**Author:** ![friguzzi](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/friguzzi/32/7045_2.png) [@friguzzi](https://swi-prolog.discourse.group/u/friguzzi)\ **Post date:** [March 30, 2022, 1:52pm UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/2 "2022-03-30T13:52:14Z")
Hi Frank, findall and forall are not supported by the probabilistic semantics. They are considered as builtin predicates and evaluated as they are, so if the query involves a probabilistic atom or the meta predicate prob it doesn’t work. Best Fabrizio ---
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [March 30, 2022, 2:32pm UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/3 "2022-03-30T14:32:14Z")
> [@friguzzi](#): > > findall and forall are not supported by the probabilistic semantics So I can just have this workaround: ```prolog :- use_module( library( pita)). :- pita. :- dynamic data/1. a :- prob( a, _). b. e :- abolish(data/1), forall( prob( a, P), assertz( data(P))). :- begin_lpad. a. b :- forall( prob(a,_), true). % don't work c :- forall( a, true). % don't work d :- forall( b, true). % works % e :- db(e). % no P possible f :- forall( data(_), true). :- end_lpad. /* (ins)?- e, prob(f, P). P = 1.0. */ ``` Regards. ---
**Author:** ![friguzzi](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/friguzzi/32/7045_2.png) [@friguzzi](https://swi-prolog.discourse.group/u/friguzzi)\ **Post date:** [March 30, 2022, 5:17pm UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/4 "2022-03-30T17:17:13Z")
Yes you can but what is your use case? ---
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [March 30, 2022, 7:33pm UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/5 "2022-03-30T19:33:46Z")
I have no concrete usecase, just playing around and learning. For instance this: ```prolog :- begin_lpad. b(x) : 0.6; b(y) : 0.4. a : P2 :- findall( X-P, prob( b(X), P), L), postprocess(L, P2). :- end_lpad. ``` I want to gather probabilities of a predicate (b) in a list and postprocess them before I set a new probability for the predicate (a). but maybe I should write something like: ```prolog b(x,0.6). b(y,0.4). :- begin_lpad. b(X) : P :- db( b(X,P)). a : P2 :- findall( X-P, b(X, P), L), postprocess(L, P2). :- end_lpad. ``` This should work. ---
**Author:** ![Frank\_Schwidom](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/frank_schwidom/32/7662_2.png) [@Frank\_Schwidom](https://swi-prolog.discourse.group/u/Frank_Schwidom)\ **Post date:** [March 30, 2022, 9:17pm UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/6 "2022-03-30T21:17:46Z")
> [@friguzzi](#): > > Yes you can but what is your use case? Now I have a working example: ```prolog :- use_module( library(pita)). :- pita. b(x,0.6). b(y,0.4). :- begin_lpad. b : P :- db( b(X,P)). b(X) : P :- db( b(X,P)). c :- b(X1), b(X2), X1 \== X2. postprocess( []). postprocess( L) : P:- true , L = [_X-P|T] , postprocess(T) . a :- findall( X-P, b(X, P), L), postprocess(L). :- end_lpad. /* (ins)?- prob( a, P). P = 0.24. (cmd)?- prob( c, P). P = 0.24. (ins)?- prob( b, P). P = 0.76. (ins)?- prob( b(X), P). X = x, P = 0.6 ; X = y, P = 0.4. */ ``` a does the same as c but a is more flexible. So I could extend b/2 on top and a would be up to date. c in the other hand should be updated as well on every step to work correctly. And maybe I would be able to derive the last b/2 from al other b/2’s so that the P sum is always 1. But I encountered a little trap. I made a mistake by writing ‘b(X) : P : db( b(X,P)).’ instead of ‘b(X) : P :- db( b(X,P)).’ and I didn’t see the mistake. And I wondered why it does not work. Next time I will look if this syntactic variation can be used for something useful. Regards. ---
**Author:** ![friguzzi](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/friguzzi/32/7045_2.png) [@friguzzi](https://swi-prolog.discourse.group/u/friguzzi)\ **Post date:** [March 31, 2022, 8:35am UTC](https://swi-prolog.discourse.group/t/cplint-pita-forall-findall-bug/5189/7 "2022-03-31T08:35:27Z")
> > ![](https://global.discourse-cdn.com/free1/uploads/swiprolog/original/2X/3/3a332e193defac4b86af14a6923225ff380696ea.png "Frank\_Schwidom") | [Frank\_Schwidom](https://swi-prolog.discourse.group/u/frank_schwidom) > > March 30 | > > > > - | - | > > > ![](https://global.discourse-cdn.com/free1/uploads/swiprolog/original/2X/d/d027fffd113beb3bf89254b51ff5f71d09894d88.png)friguzzi: > > > > Yes you can but what is your use case? > > Now I have a working example: > > ```prolog > > :- use_module( library(pita)). > > :- pita. > > b(x,0.6). > > b(y,0.4). > > :- begin_lpad. > > b : P :- db( b(X,P)). > > b(X) : P :- db( b(X,P)). > > c :- b(X1), b(X2), X1 \== X2. > > postprocess( []). > > postprocess( L) : P:- true > > , L = [_X-P|T] > > , postprocess(T) > > . > > a :- findall( X-P, b(X, P), L), postprocess(L). > > :- end_lpad. > > /* > > (ins)?- prob( a, P). > > P = 0.24. > > (cmd)?- prob( c, P). > > P = 0.24. > > (ins)?- prob( b, P). > > P = 0.76. > > (ins)?- prob( b(X), P). > > X = x, > > P = 0.6 ; > > X = y, > > P = 0.4. > > */ > > ``` > > a does the same as c but a is more flexible. So I could extend b/2 on top and a would be up to date. > c in the other hand should be updated as well on every step to work correctly. > > And maybe I would be able to derive the last b/2 from al other b/2’s so that the P sum is always 1. > > But I encountered a little trap. I made a mistake by writing ‘b(X) : P : db( b(X,P)).’ instead of ‘b(X) : P :- db( b(X,P)).’ and I didn’t see the mistake. And I wondered why it does not work. Next time I will look if this syntactic variation can be used for something useful. I believe b(X) : P : db( b(X,P)) will be interpreted as a fact, not as a probabilistic fact, that’s why it didn’t work Fabrizio