error-handlingprologclprinstantiation-error

Arguments are not sufficiently instantiated in prolog


I'm trying to run this code but I get this error anytime I use this query: gp174(P, S). ERROR: >=/2: Arguments are not sufficiently instantiated.

and this is my code:

call_option(B,S,C,E,P) :- 
    0 =< S, 
    S =< E / 100, 
    P = -C * B.

call_option(B,S,C,E,P) :- 
    S >= E / 100, 
    P = (100 * S - E - C) * B.

gp173(P) :- 
    call_option(1, 7, 200, 300, P).

% butterfly strike p174.
butterfly(S, H) :- 
    H = P1 + 2*P2 + P3,
    Buy = 1, Sell = -1,
        call_option(Buy, S, 100, 500, P1),
        call_option(Sell, S, 200, 300, P2),
        call_option(Buy, S, 400, 100, P3).

% goal for butterfly strike

gp174(P,S) :- 
    P >= 0, 
    butterfly(S,P).

What should I do?
Where should I load my clpr library?


Solution

  • I tried to modify using the documented library:

    :- [library(clpr)].
    
    call_option(B,S,C,E,P) :-
        {0 =< S},
        {S =< E / 100},
        {P = -C * B}.
    
    call_option(B,S,C,E,P) :-
        {S >= E / 100},
        {P = (100 * S - E - C) * B}.
    
    gp173(P) :-
        call_option(1, 7, 200, 300, P).
    
    % butterfly strike p174.
    butterfly(S, H) :-
        {H = P1 + 2*P2 + P3,
        Buy = 1, Sell = -1},
            call_option(Buy, S, 100, 500, P1),
            call_option(Sell, S, 200, 300, P2),
            call_option(Buy, S, 400, 100, P3).
    
    % goal for butterfly strike
    
    gp174(P,S) :-
        {P >= 0},
        butterfly(S,P).
    

    and this is the result:

    ?- gp174(P,S).
    {S=2.0+0.01*P, P=<100.0, _G56405= -300.0+P, P>=0.0} ;
    {S=4.0-0.01*P, P=<100.0, _G59475= -100.0-P, _G59488=100.0+P, P>=0.0} ;
    false.
    

    HTH