Re: An example of finite domain?

[PRADOS Julien]

it doesn't look like a Finite Domain (FD) problem !!!

so try clip (aviable only under linux):  
       http://interval.sourceforge.net/interval/prolog/clip/

0) install gprolog under Linux
1) install clip
2) consult the following predicat

domino(A1,A2,Q) :-
       {X1 = 20 * sin(A1), Y1 = 10 * cos(A1),
        X2 = 20 * sin(A2), Y2 = 10 * cos(A2),
        X3 = 0, Y3 = 0,
        VX1 = X2 - X3, VY1 = Y2 - Y3,
        VX2 = X1 - X2, VY2 = Y1 - Y2,
        Q = VX1*VX2 + VY1*VY2
       }.

by typing:

| ?- consult(domino).

and enter the following query

| ?- reset_clip,                                                        
                   %reset the solver
     {A1 >= 0,A1 =< (pi/2), A2 >= 0, A2 =< (pi/2),Q >= 0},        %add 
constraint on A1,A2,Q
     domino(A1,A2,Q),                                                
               %add the domino constraints
     solve_clip([A1,A2,Q],0.01),                                     
           %solve the system with a precision of 0.01
     print_clip([A1,A2,Q]).                                            
              %display the variables


for this query I have obtain the following result

[$INT(1),$INT(11),$INT(43)]
x(1)=
  [1.57079632679489655799898173427,
   1.5707963267948967800435866593]
x(11)=
  [1.57079632679489655799898173427,
   1.5707963267948967800435866593]
x(43)=
  [0,
   7.10542735760100185871124267578e-14]

it means that if there is solutions... there are in those intervals...
so certainly ther is no solution for those constraints.



Jul

PS: I have modified VY2 = Y2-Y3 to VY1 = Y2 - Y3.... because I think it 
is a mistake...






address@hidden wrote:

> I am new to GNU-Prolog and I have a problem that I wish to solve
> (I am trying to write a domino game and am trying to figure out how to 
> lay
> out the dominoes without them crossing).  Below is an except from that 
> process.
>
> Given two angles A1 and A2, X1 = 20*sin(A1), Y1 = 10*cos(A1), X2 = 
> 20*sin(A2),
> Y2 = 10*cos(A2).  Also X3 = 0, Y3 = 0.
> Let VX1 = X2-X3, VY2 = Y2-Y3, VX2 = X1-X2, VY2=Y1-Y2.
> Compute a function Q = VX1*VX2+VY1*VY2.
>
> Make the domain of A1 and A2 equal to 0 ... 90.  Constrain the 
> expression Q > 0 to equal true.  Minimize the sum of angles A1 and A2.
>
> I have tried solving the problem myself, but I am getting errors.  Can 
> anyone help me please :-)?
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Users-prolog mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/users-prolog


domino(A1,A2,Q) :-
        {X1 = 20 * sin(A1), Y1 = 10 * cos(A1),
         X2 = 20 * sin(A2), Y2 = 10 * cos(A2),
         X3 = 0, Y3 = 0, 
         VX1 = X2 - X3, VY1 = Y2 - Y3,
         VX2 = X1 - X2, VY2 = Y1 - Y2,
         Q = VX1*VX2 + VY1*VY2
        }.