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pl:prolog:pllib:scheduling [2019/06/27 15:50] |
pl:prolog:pllib:scheduling [2019/06/27 15:50] (aktualna) |
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| + | ====== Scheduling ====== | ||
| + | {{tag>planning}} | ||
| + | ===== Description ===== | ||
| + | Scheduling with precedence constraints and no resource constraints. | ||
| + | |||
| + | **Source**: PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7. | ||
| + | ===== Download ===== | ||
| + | Program source code: {{scheduling.pl}} | ||
| + | ===== Listing ===== | ||
| + | <code prolog> | ||
| + | % Figure 14.3 Scheduling with precedence constraints and no resource constraints. | ||
| + | |||
| + | |||
| + | % Scheduling with CLP with unlimited resources | ||
| + | |||
| + | schedule( Schedule, FinTime) :- | ||
| + | tasks( TasksDurs), | ||
| + | precedence_constr( TasksDurs, Schedule, FinTime), % Construct precedence constraints | ||
| + | minimize( FinTime). | ||
| + | |||
| + | precedence_constr( [], [], FinTime). | ||
| + | |||
| + | precedence_constr( [T/D | TDs], [T/Start/D | Rest], FinTime) :- | ||
| + | Start >= 0, % Earliest start at 0 | ||
| + | Start + D =< FinTime, % Must finish by FinTime | ||
| + | precedence_constr( TDs, Rest, FinTime), | ||
| + | prec_constr( T/Start/D, Rest). | ||
| + | |||
| + | prec_constr( _, []). | ||
| + | |||
| + | prec_constr( T/S/D, [T1/S1/D1 | Rest]) :- | ||
| + | ( prec( T, T1), !, { S+D =< S1} | ||
| + | ; | ||
| + | prec( T1, T), !, { S1+D1 =< S} | ||
| + | ; | ||
| + | true ), | ||
| + | prec_constr( T/S/D, Rest). | ||
| + | |||
| + | % List of tasks to be scheduled | ||
| + | |||
| + | tasks( [ t1/5, t2/7, t3/10, t4/2, t5/9]). | ||
| + | |||
| + | % Precedence constraints | ||
| + | |||
| + | prec( t1, t2). prec( t1, t4). prec( t2, t3). prec( t4, t5). | ||
| + | </code> | ||
| + | ===== Comments ===== | ||
