documents/tutorial/propiachr.tex

38 the start times $S1$ and $S2$
41 {\em noclash} $ \Leftrightarrow (S1 >= S2 + 5 \vee S2 >= S1 + 5)$.
44 noclash(S1,S2) :-
45     ic:(S1 \$>= S2+5).
46 noclash(S1,S2) :-
47     ic:(S2 \$>= S1+5).
63 noclash(S1,S2) <=> ic:(S2 #< S1+5) | ic:(S1 #>= S2+5).
64 noclash(S1,S2) <=> ic:(S1 #< S2+5) | ic:(S2 #>= S1+5).
70 ?- ic:([S1,S2]::1..10),
71    noclash(S1,S2),
72    S1 #>= 6.
77 However, after imposing $S1>=6$,
78 the domain of $S1$ is reduced to \verb96..109.
81 condition $S1+5 >= S2$ is entailed,
91 ?-      [S1,S2]::1..10,
92         noclash(S1,S2) infers most,
93         S1 #>= 6.
100 %?- [S1,S2]::1..10, noclash(S1,S2) infers most, S1 #>= 6
536 noclash(S1,S2) <=> ic:(S2 #< S1+5) | ic:(S1 #>= S2+5).
537 noclash(S1,S2) <=> ic:(S1 #< S2+5) | ic:(S2 #>= S1+5).
546 ?- ic:([S1,S2]::1..10),
547    noclash(S1,S2),
548    S1 #>= 6.
559 In this example, therefore, \verb0noclash(S1,S2)0 is replaced by
583 ?- ic:([S1,S2]::1..10),
584    noclash(S1,S2),
585    before(S1,S2).
590 The two constraints can be combined so as to propagate $S2 \ge S1+5$
595 noclash(S1,S2), before(S1,S2) ==> ic:(S2 #>= S1+5).
604 $prec(S1,D,S2)$ holds if the time $S1$ precedes the time $S2$ by at
606 For the following code to work, $S1$ and $S2$ may be numbers or
611 prec(S1,0,S2), prec(S2,0,S1) <=> S1=S2.
612 prec(S1,D1,S2), prec(S2,D2,S3) ==> D3 is D1+D2, prec(S1,D3,S3).
613 prec(S1,D1,S2) \verb.\. prec(S1,D2,S2) <=> D2=<D1 | true.     % Simpagation
615 noclash(S1,S2), prec(S1,D,S2) ==> D > -5 | prec(S1,5,S2).
616 noclash(S1,S2), prec(S2,D,S1) ==> D > -5 | prec(S2,5,S1).
744 \verb0prec(S1,D,S2)0 above.