Re: [Help-glpk] var between 2 parameters

[Paolo Tofoni]

Dear Mate,
thanks a lot for your help, really I'm try to consider in the
following job shop model:

/* Data Table 1. Tasks consist of Job, Machine, Dur data*/
set TASKS dimen 2;
param dur{TASKS};
/* Data Table 2 */
set TASKORDER within {TASKS,TASKS};
/* JOBS and MACHINES are inferred from the data tables*/
set JOBS := setof {(j,m) in TASKS} j;
set MACHINES := setof {(j,m) in TASKS} m;
/* Decision variables are start times for tasks, and the makespan */
var start{TASKS} >= 0;
var makespan >= 0;

/* BigM is set to be bigger than largest possible makespan */
param BigM := 1 + sum {(i,m) in TASKS} dur[i,m];

/* The primary objective is to minimize makespan, with a secondary
objective of starting tasks as early as possible */
minimize OBJ: BigM*makespan + sum{(i,m) in TASKS} start[i,m];

/* By definition, all jobs must be completed within the makespan */
s.t. A {(j,m) in TASKS}: start[j,m] + dur[j,m] <= makespan;

/* Must satisfy any orderings that were given for the tasks. */
s.t. B {(i,m,j,n) in TASKORDER}: start[i,m] + dur[i,m] <= start[j,n];

/* Eliminate conflicts if tasks are require the same machine */
/* y[i,m,j] = 1 if Job i is scheduled before job j on machine m*/

var y{(i,m) in TASKS,(j,m) in TASKS: i < j} binary;

s.t. C {(i,m) in TASKS,(j,m) in TASKS: i < j}:
   start[i,m] + dur[i,m] <= start[j,m]+ BigM*(1-y[i,m,j]);

s.t. D {(i,m) in TASKS,(j,m) in TASKS: i < j}:
   start[j,m] + dur[j,m] <= start[i,m] + BigM*y[i,m,j];

solve;

printf "\n\nMakespan = %5.2f\n",makespan;

/* Post solution, compute finish times for each task to use in report */
param finish{(j,m) in TASKS} := start[j,m] + dur[j,m];

/* Task Summary Report */
printf "\n                TASK SUMMARY\n";
printf "\n     JOB   MACHINE     Dur   Start  Finish\n";
printf {(i,m) in TASKS} "%8s  %8s   %5.2f   %5.2f   %5.2f\n",
   i, m, dur[i,m], start[i,m], finish[i,m];

/* Schedule of activities for each job */
set M{j in JOBS} := setof {(j,m) in TASKS} m;
param r{j in JOBS, m in M[j]} :=
   1+sum{n in M[j]: start[j,n]<start[j,m] || start[j,n]==start[j,m] && n<m} 1;
printf "\n\n           JOB SCHEDULES\n";
for {j in JOBS} {
   printf "\n%s:\n",j;
   printf "         MACHINE   Start   Finish\n";
   printf {k in 1..card(M[j]), m in M[j]: k==r[j,m]}
      " %15s   %5.2f    %5.2f\n",m, start[j,m],finish[j,m];
}

/* Schedule of activities for each machine */
set J{m in MACHINES} := setof {(j,m) in TASKS} j;
param s{m in MACHINES, j in J[m]} :=
   1+sum{k in J[m]: start[k,m]<start[j,m] || start[k,m]==start[j,m] && k<j} 1;
printf "\n\n         MACHINE SCHEDULES\n";
for {m in MACHINES} {
   printf "\n%s:\n",m;
   printf "             JOB   Start   Finish\n";
   printf {k in 1..card(J[m]), j in J[m]: k==s[m,j]}
    " %15s   %5.2f    %5.2f\n",j, start[j,m],finish[j,m];
}
printf "\n\n";

data;

/* Job shop data from Christelle Gueret, Christian Prins,  Marc Sevaux,
"Applications of Optimization with Xpress-MP," Chapter 5, Dash
Optimization, 2000. */

/* Jobs are broken down into a list of tasks, each task described by
job name, machine name, and duration */

param: TASKS: dur :=
   Paper_1  Blue    45
   Paper_1  Yellow  10
   Paper_2  Blue    20
   Paper_2  Green   10
   Paper_2  Yellow  34
   Paper_3  Blue    12
   Paper_3  Green   17
   Paper_3  Yellow  28 ;

/* List any required pairwise orderings of tasks */

set TASKORDER :=
   Paper_1 Blue    Paper_1 Yellow
   Paper_2 Green   Paper_2 Blue
   Paper_2 Blue    Paper_2 Yellow
   Paper_3 Yellow  Paper_3 Blue
   Paper_3 Blue    Paper_3 Green ;

end;


writed by Jeff Kantor the shift calendars of the machine and I guess
that the best way could be to create a list of day off  ( where the
production is stopped) and I'm going to add to task lead time  (start
+ duration) the sum of the  durations of the day off (between start
and start + duration)
it's difficult to explain and I hope to be being clear.
Tks again