(!****************************************************************
   CP example problems
   ===================
   
   file taskserializer.mos
   ```````````````````````
   Resource-constrained project planning problem (construction of 
   a house) modeled with task and resource objects.
   - Defining a task-based branching strategy -

   *** This model cannot be run with a Community Licence ***  

   (c) 2008 Artelys S.A. and Fair Isaac Corporation
       rev. Apr. 2022
*****************************************************************!)
model "Tasks serialization example"  
 uses "kalis"
 
 declarations
  Masonry, Carpentry, Roofing, Windows, Facade, Garden, Plumbing, 
    Ceiling, Painting, MovingIn : cptask    ! Declaration of tasks
  Taskset : set of cptask
  money_available : cpresource              ! Resource declaration
 end-declarations

 forward function selectNextTask(tasks: cptasklist) : integer 

! 'money_available' is a cumulative resource with max. amount of 29$
 set_resource_attributes(money_available,KALIS_DISCRETE_RESOURCE,29)

! Limit resource availability to 20$ in the time interval [0,14]
 setcapacity(money_available, 0, 14, 20)

! Setting the task durations and predecessor sets
 set_task_attributes(Masonry  , 7) 
 set_task_attributes(Carpentry, 3, {Masonry})
 set_task_attributes(Roofing  , 1, {Carpentry})
 set_task_attributes(Windows  , 1, {Roofing})
 set_task_attributes(Facade   , 2, {Roofing})
 set_task_attributes(Garden   , 1, {Roofing})
 set_task_attributes(Plumbing , 8, {Masonry})
 set_task_attributes(Ceiling  , 3, {Masonry})
 set_task_attributes(Painting , 2, {Ceiling}) 
 set_task_attributes(MovingIn , 1, {Windows,Facade,Garden,Painting})

! Setting the resource consumptions
 consumes(Masonry  , 7, money_available)
 consumes(Carpentry, 3, money_available)
 consumes(Roofing  , 1, money_available)
 consumes(Windows  , 1, money_available)
 consumes(Facade   , 2, money_available)
 consumes(Garden   , 1, money_available)
 consumes(Plumbing , 8, money_available)
 consumes(Ceiling  , 3, money_available)
 consumes(Painting , 2, money_available)
 consumes(MovingIn , 1, money_available)

! Set of tasks to schedule
 Taskset := {Masonry, Carpentry, Roofing, Windows, Facade, Garden,
             Plumbing, Ceiling, Painting, MovingIn}

! Set the custom branching strategy using task_serialize:
! - the task serialization process will use the function
!   "selectNextTask" to look for the next task to fix
! - it will use the "KALIS_MAX_TO_MIN" value selection heuristic
!   to set the tasks duration variable
! - and the "KALIS_MIN_TO_MAX" value selection heuristic to set
!   the start of the task
 cp_set_branching(task_serialize(->selectNextTask, 
                  KALIS_MAX_TO_MIN, KALIS_MIN_TO_MAX, Taskset))
 
! Find the optimal schedule (minimizing the makespan)
 if 0 <> cp_schedule(getmakespan) then 
   cp_show_sol  
 else
   writeln("No solution found")
 end-if

!-------------------------------------------------------------
! **** Function to select the next task to schedule
 function selectNextTask(tasks: cptasklist) : integer 
  write("selectNextTask : ")
  declarations
   Vset,Iset: set of integer
  end-declarations

 ! Get the number of elements of "tasks"
  listsize:= getsize(tasks)  

 ! Set of uninstantiated variables
  forall(i in 1..listsize) 
   if not is_fixed(getstart(gettask(tasks,i))) or 
      not is_fixed(getduration(gettask(tasks,i))) then 
     Vset+= {i};     
   end-if
 
  if Vset={} then
    returned:= 0
  else    
  ! Get the variables with max. degree
    dmax:= max(i in Vset) getsize(getduration(gettask(tasks,i))) 
    forall(i in Vset)
      if getsize(getduration(gettask(tasks,i))) = dmax then 
       Iset+= {i}; end-if
    dsize:= MAX_INT

  ! Choose var. with smallest domain among those indexed by 'Iset'
    forall(i in Iset)
      if getsize(getstart(gettask(tasks,i))) < dsize then
        returned:= i
        dsize:= getsize(getstart(gettask(tasks,i))) 
      end-if 
  end-if 

  if returned <> 0 then
   writeln(gettask(tasks,returned))
  end-if
 end-function

end-model