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Scheduling problems Description
Further explanation of this example: 'Applications of optimization with Xpress-MP', Chapter 7: Scheduling problems
Source Files
Data Files
b1stadium.mos (!****************************************************** Mosel Example Problems ====================== file b1stadium.mos `````````````````` Construction of a stadium (c) 2008 Fair Isaac Corporation author: S. Heipcke, Mar. 2002, rev. Oct 2009 *******************************************************!) model "B-1 Stadium construction" uses "mmxprs" forward procedure print_sol declarations N = 19 ! Number of tasks in the project ! (last = fictitious end task) TASKS=1..N ARC: dynamic array(TASKS,TASKS) of real ! Matrix of the adjacency graph DUR: array(TASKS) of real ! Duration of tasks start: array(TASKS) of mpvar ! Start times of tasks obj1: real ! Solution of first problem end-declarations initializations from 'b1stadium.dat' ARC DUR end-initializations ! Precedence relations between tasks forall(i,j in TASKS | exists(ARC(i,j))) Prec(i,j):= start(j) - start(i) >= DUR(i) ! Solve the first problem: minimize the total duration minimize(start(N)) obj1:=getobjval ! Solution printing print_sol ! **** Extend the problem **** declarations BONUS: integer ! Bonus per week finished earlier MAXW: array(TASKS) of real ! Max. reduction of tasks (in weeks) COST: array(TASKS) of real ! Cost of reducing tasks by a week save: array(TASKS) of mpvar ! Number of weeks finished early end-declarations initializations from 'b1stadium.dat' MAXW BONUS COST end-initializations ! Second objective function Profit:= BONUS*save(N) - sum(i in 1..N-1) COST(i)*save(i) ! Redefine precedence relations between tasks forall(i,j in TASKS | exists(ARC(i,j))) Prec(i,j):= start(j) - start(i) + save(i) >= DUR(i) ! Total duration start(N) + save(N) = obj1 ! Limit on number of weeks that may be saved forall(i in 1..N-1) save(i) <= MAXW(i) ! Solve the second problem: maximize the total profit maximize(Profit) ! Solution printing writeln("Total profit: ", getsol(Profit)) print_sol !----------------------------------------------------------------- procedure print_sol writeln("Total duration: ", getsol(start(N)), " weeks") forall(i in 1..N-1) write(strfmt(i,2), ": ", strfmt(getsol(start(i)),-3), if(i mod 9 = 0,"\n","")) writeln end-procedure end-model | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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