/usr/share/Yap/problog_examples/graph.pl is in yap 6.2.2-6.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | %%% -*- Mode: Prolog; -*-
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% ProbLog program describing a probabilistic graph
% (running example from ProbLog presentations)
% $Id: graph.pl 4875 2010-10-05 15:28:35Z theo $
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:- use_module(library(problog)).
%%%%
% background knowledge
%%%%
% definition of acyclic path using list of visited nodes
path(X,Y) :- path(X,Y,[X],_).
path(X,X,A,A).
path(X,Y,A,R) :-
X\==Y,
edge(X,Z),
absent(Z,A),
path(Z,Y,[Z|A],R).
% using directed edges in both directions
edge(X,Y) :- dir_edge(Y,X).
edge(X,Y) :- dir_edge(X,Y).
% checking whether node hasn't been visited before
absent(_,[]).
absent(X,[Y|Z]):-X \= Y, absent(X,Z).
%%%%
% probabilistic facts
%%%%
0.9::dir_edge(1,2).
0.8::dir_edge(2,3).
0.6::dir_edge(3,4).
0.7::dir_edge(1,6).
0.5::dir_edge(2,6).
0.4::dir_edge(6,5).
0.7::dir_edge(5,3).
0.2::dir_edge(5,4).
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% example queries about path(1,4)
%
%%% explanation probability (and facts involved)
% ?- problog_max(path(1,4),Prob,FactsUsed).
% FactsUsed = [dir_edge(1,2),dir_edge(2,3),dir_edge(3,4)],
% Prob = 0.432 ?
% yes
%%% success probability
% ?- problog_exact(path(1,4),Prob,Status).
% 8 proofs
% Prob = 0.53864,
% Status = ok ?
% yes
%%% lower bound using 4 best proofs
% ?- problog_kbest(path(1,4),4,Prob,Status).
% 4 proofs
% Prob = 0.517344,
% Status = ok ?
% yes
%%% approximation using monte carlo, to reach 95%-confidence interval width 0.01
% ?- problog_montecarlo(path(1,4),0.01,Prob).
% Prob = 0.537525 ?
% yes
%%% upper and lower bound using iterative deepening, final interval width 0.01
% ?- problog_delta(path(1,4),0.01,Bound_low,Bound_up,Status).
% Bound_low = 0.5354096,
% Bound_up = 0.53864,
% Status = ok ?
% yes
%%% upper and lower bound obtained cutting the sld tree at probability 0.1 for each branch
% ?- problog_threshold(path(1,4),0.1,Bound_low,Bound_up,Status).
% 4 proofs
% Bound_low = 0.517344,
% Bound_up = 0.563728,
% Status = ok ?
% yes
%%% lower bound obtained cutting the sld tree at probability 0.2 for each branch
% ?- problog_low(path(1,4),0.2,Bound_low,Status).
% 1 proofs
% Bound_low = 0.432,
% Status = ok ?
% yes
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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