Question

我有一个家庭作业，在prolog中定义10个事实来解决这个难题。

Five translators are working in an international organization:
Spaniard, Englishman, Frenchman, German and Russian.
Each of them speaks its native language and also two
languages from the native languages of other translators. Find
the languages speaked by each translator if it is known that
1. The Englishman speaks German.
2. The Spaniard speaks French.
3. The German does not speak Spanish.
4. The Frenchman does not speak German.
5. Spaniard and Englishman can talk with each other in German.
6. Englishman and Frenchman can talk with each other in two
languages.
7. Four translators speak Russian.
8. Exactly two translators speak French.
9. Only one translator who speaks Spanish speaks also Russian.
10. Russian and Englishman have no common languages except
their native languages.

我已经定义了8个约束并将我的解决方案空间减少到15.但我不知道如何定义最后两个事实。

% lahendusstruktuur
structure(
  [translator(inglane,_,_,inglise),
   translator(sakslane,_,_,saksa),
   translator(hispaanlane,_,_,hispaania),
   translator(prantslane,_,_,prantsuse),
   translator(venelane,_,_,vene)]).

% abipredikaadid
nationality(translator(B,_,_,_),B).
language1(  translator(_,B,_,_),B).
language2(  translator(_,_,B,_),B).
native_language(
            translator(_,_,_,B),B).

% keelte faktid (andmebaas)
possible_language(vene).
possible_language(inglise).
possible_language(hispaania).
possible_language(prantsuse).
possible_language(saksa).

% tabeli täitmine
solve(S):-
    structure(S),
    fill_structure(S),
    fact1(S),
    fact2(S),
    fact3(S),
    fact4(S),
    fact5(S),
    fact6(S),
    fact7(S),
    fact8(S),
    %fact9(S),
    %fact10(S),
    true.

fill_structure([A,B,C,D,E]):-
    fill_line(A,inglane),
    fill_line(B,sakslane),
    fill_line(C,hispaanlane),
    fill_line(D,prantslane),
    fill_line(E,venelane).

fill_line(X,Nationality):-
    nationality(X,Nationality),
    possible_language(Keel1),
    language1(X,Keel1),
    possible_language(Keel2),
    language2(X,Keel2),
    native_language(X,Native),
    Keel1\=Native,
    Keel2\=Native,
    Keel1 @> Keel2.

% keelte generaator
speaks(Nationality,Language,S):-
    member(X,S),
    nationality(X,Nationality),
    language(X,Language).

language(X,L):-native_language(X,L).
language(X,L):-language1(X,L).
language(X,L):-language2(X,L).

% faktid 1-10
%1. The Englishman speaks German.
fact1(X):-
   speaks(inglane,saksa,X).
%2. The Spaniard speaks French.
fact2(X):-
   speaks(hispaanlane,saksa,X).
%3. The German does not speak Spanish.
fact3(X):-
   \+speaks(sakslane,hispaania,X).

% The Frenchman does not speak German.
fact4(X):-
     \+speaks(prantslane,saksa,X).

% Spaniard and Englishman can talk with each other in German.
fact5(X):-
  speaks(hispaanlane,saksa,X),
  speaks(inglane,saksa,X).

%6. Englishman and Frenchman can talk with each other in two languages.
fact6(X):-
    findall(Keel,
      (
      speaks(inglane,Keel,X),
      speaks(prantslane,Keel,X)
      ),
      Keelte_hulk),
      Keelte_hulk=[_,_].

%% Four translators speak Russian.
fact7(X):-
  findall(Inimene,
  (
  speaks(Inimene,vene,X),
  speaks(Inimene,vene,X),
  speaks(Inimene,vene,X),
  speaks(Inimene,vene,X)),Inimeste_hulk),
  Inimeste_hulk=[_,_,_,_].
 /*
  (speaks(inglane,vene,X), 
  speaks(sakslane, vene,X), 
  speaks(hispaanlane, vene,X), 
  \+ speaks(prantslane, vene,X));
  (speaks(inglane,vene,X), 
  speaks(sakslane, vene,X), 
  \+speaks(hispaanlane, vene,X), 
  speaks(prantslane, vene,X));
  (speaks(inglane,vene,X), 
  \+speaks(sakslane, vene,X), 
  speaks(hispaanlane, vene,X), 
  speaks(prantslane, vene,X));
  (speaks(inglane,vene,X), 
  \+speaks(sakslane, vene,X), 
  speaks(hispaanlane, vene,X), 
  speaks(prantslane, vene,X)). */

  %Exactly two translators speak French.
fact8(X):-
    findall(Inimene,
  (
  speaks(Inimene,prantsuse,X),
  speaks(Inimene,prantsuse,X)),Inimeste_hulk),
  Inimeste_hulk=[_,_].

例如，我为事实10尝试了这样的解决方案。

   fact10(X):-
     speaks(inglane,inglise,X), speaks(venelane,inglise,X),
     speaks(venelane,inglise,X), speaks(venelane,vene,X),
     \=(speaks(inglane,hispaania,X),speaks(venelane, hispaania,X),
     \=(speaks(inglane,prantsuse,X),speaks(venelane, prantsuse,X),
     \=(speaks(inglane,saksa,X),speaks(venelane,saksa,X).

这会减少解决方案空间，但之后它仍然包含不应该在简化解集中的元素。

我正在使用此功能来获取我的解决方案集大小

findall(_, solve(X), Solutions), length(Solutions,N).

这适用于解决方案集元素

solve(X).

我没有想法如何描述这两个事实。如果有人可以提供帮助，我将不胜感激:)。

对不起我的英语，这不是我的第一语言。

Answer 1

与您的不同的方法是使用具有有限域的约束编程构造（即Prolog的clpfd库）。这是这个问题的两个MiniZinc模型，可能会给你一些灵感。由于这是一个家庭作业，我甚至不会尝试用“纯”Prolog解决它，即没有clpfd。

这是一个使用集合数组的模型：http://hakank.org/minizinc/five_translators.mzn

采用相同的主要方法，但改为使用0/1矩阵：http://hakank.org/minizinc/five_translators.mzn

（我不确定这会对你有所帮助，但这是一个有趣的问题......）

Answer 2

我认为这种关系可以解决规则9中的问题：http://www.swi-prolog.org/pldoc/man?predicate=bagof%2f3

像

这样的东西

bagof(Translator,(some condition, possibly with commas or semicolons in it, 
                  verifying that Translator speaks those two languages), 
      Translators),

这里的bagof条款

标识一个变量（第一个参数）来表示我们对
设置涉及该变量的条件，以任何方式解决Prolog可以
将所有适用该条件的变量收集到一个列表（第三个参数）

然后验证列表的长度为1。

我不想为你做功课，所以我不能填写这个条件，但是如果你正在寻找所有有长颈鹿和喝伏特加酒的翻译，那就是

(has(Translator,giraffe),drinks(Translator,vodka))

bagof也可用于条件10。

Prolog逻辑谜题＆amp;约束编程

2 个答案: