39 lines
642 B
Prolog
39 lines
642 B
Prolog
% Thom Fruehwirth, LMU, 980129, 980311
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:- use_module(library(chr)).
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handler pathc.
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option(already_in_heads,on).
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constraints c/3.
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% c(X,Y,N): the distance between variables X and Y is the positive number N
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c(I,J,A),c(I,J,B) <=> C is min(A,B), c(I,J,C).
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c(I,J,A),c(J,K,B) ==> C is A+B, c(I,K,C).
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% Only complete if both c(I,J,D) and c(J,I,D) are present for each constraint
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/*
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% Queries
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c(A,B,D).
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c(A,B,2),c(A,B,4).
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c(A,B,2),c(B,C,3).
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c(A,B,2),c(B,A,1).
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c(A,B,2),c(B,A,0).
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c(A,B,2),c(A,C,3),c(C,B,2).
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c(A,B,2),c(A,C,3),c(C,B,4).
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c(A,B,2),c(B,C,3),c(C,A,4).
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c(A,B,2),c(B,C,3),c(C,A,4),c(B,A,2),c(C,B,3),c(A,C,4).
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*/
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