| |||||||||||||||
'producer_consumer' constraints: solving a resource-constrained project scheduling problem Description So-called 'producer_consumer' relations combine tasks that produce or consume quantities of the same non-renewable resource. Such problems may be modeled in two ways, namely
Source Files By clicking on a file name, a preview is opened at the bottom of this page.
producer_consumer_alt.mos (!**************************************************************** CP example problems =================== file producer_consumer_alt.mos `````````````````````````````` Resource-constrained project planning problem (construction of a house) modeled with a producer-consumer constraint. *** This model cannot be run with a Community Licence *** (c) 2008 Artelys S.A. and Fair Isaac Corporation Creation: 2007, rev. Mar. 2013 *****************************************************************!) model "Cumulative Scheduling" uses "kalis" setparam("KALIS_DEFAULT_LB",0) setparam("KALIS_DEFAULT_UB",100) declarations ! Task indices Masonry = 1; Carpentry= 2; Roofing = 3; Windows = 4 Facade = 5; Garden = 6; Plumbing = 7; Ceiling = 8 Painting= 9; MovingIn =10; InitialPayment=11; SecondPayment=12 BUILDTASKS = 1..10 PAYMENTS = 11..12 TASKS = BUILDTASKS+PAYMENTS TNAMES: array(TASKS) of string obj:cpvar ! Objective variable starts : array(TASKS) of cpvar ! Start times variables ends : array(TASKS) of cpvar ! Completion times durations: array(TASKS) of cpvar ! Durations of tasks consos : dynamic array(TASKS) of cpvar ! Res. consumptions sizes : dynamic array(TASKS) of cpvar ! Consumption sizes prods : dynamic array(TASKS) of cpvar ! Res. production sizep : dynamic array(TASKS) of cpvar ! Production sizes Strategy : cpbranching ! Branching strategy end-declarations TNAMES:: (1..12)["Masonry", "Carpentry", "Roofing", "Windows", "Facade", "Garden", "Plumbing", "Ceiling", "Painting", "MovingIn", "InitialPayment", "SecondPayment"] ! Setting the names of the variables forall(j in TASKS) do starts(j).name := TNAMES(j)+".start" ends(j).name := TNAMES(j)+".end" durations(j).name := TNAMES(j)+".duration" end-do ! Creating consumption variables forall(j in BUILDTASKS) do create(sizes(j)) sizes(j).name := TNAMES(j)+".size" create(consos(j)) consos(j).name := TNAMES(j)+".conso" end-do ! Setting durations of building tasks durations(Masonry) =7; durations(Carpentry)=3; durations(Roofing) =1 durations(Windows) =1; durations(Facade) =2; durations(Garden) =1 durations(Plumbing)=8; durations(Ceiling) =3; durations(Painting)=2 durations(MovingIn)=1 ! Precedence constraints among building tasks starts(Carpentry) >= ends(Masonry) starts(Roofing) >= ends(Carpentry) starts(Windows) >= ends(Roofing) starts(Facade) >= ends(Roofing) starts(Garden) >= ends(Roofing) starts(Plumbing) >= ends(Masonry) starts(Ceiling) >= ends(Masonry) starts(Painting) >= ends(Ceiling) starts(MovingIn) >= ends(Windows) starts(MovingIn) >= ends(Facade) starts(MovingIn) >= ends(Garden) starts(MovingIn) >= ends(Painting) ! Setting task consumptions consos(Masonry) = 7; consos(Carpentry) = 3; consos(Roofing) = 1 consos(Windows) = 1; consos(Facade) = 2; consos(Garden) = 1 consos(Plumbing) = 8; consos(Ceiling) = 3; consos(Painting) = 2 consos(MovingIn) = 1 ! Production (amount) of payment tasks forall(j in PAYMENTS) do create(prods(j)) prods(j).name := TNAMES(j)+".prod" create(sizep(j)) sizep(j).name := TNAMES(j)+".sizep" end-do ! Payment data prods(InitialPayment) = 20; prods(SecondPayment) = 9 durations(InitialPayment) = 1; durations(SecondPayment) = 1 starts(InitialPayment) = 0; starts(SecondPayment) = 15 ! Objective: makespan of the schedule obj = maximum({ ends(Masonry) , ends(Carpentry), ends(Roofing), ends(Windows), ends(Facade), ends(Garden), ends(Plumbing), ends(Ceiling), ends(Painting), ends(MovingIn)}) ! Posting the producer_consumer constraint producer_consumer(starts,ends,durations,prods,sizep,consos,sizes) ! Setting the search strategy Strategy:= assign_var(KALIS_SMALLEST_MIN, KALIS_MIN_TO_MAX, starts) cp_set_branching(Strategy) ! Find the optimal solution if cp_minimize(obj) then writeln("Minimum makespan: ", obj.sol) forall(j in BUILDTASKS) writeln(TNAMES(j), ": ", starts(j).sol, " - ", ends(j).sol) else writeln("No solution found") end-if end-model | |||||||||||||||
© Copyright 2024 Fair Isaac Corporation. |