(!******************************************************
   Mosel Example Problems
   ======================

   file burglar2.mos
   `````````````````
   Knapsack problem   
  
   A burglar considers eight items that have different values
   and weights. He wants to take a group of items that maximizes
   the total value while the total weight is not more than the
   maximum 'WTMAX' he can carry.

   This IP model represents the so-called knapsack problem where
   binary decision variable 'take(i)' takes value 1 if item 'i'
   is taken; 0 otherwise. This implementation illustrates how 
   problem data could be read into tables from text files. 
   Instead of having the item data embedded in the Mosel model 
   file, we have the data in a file and use 'initializations from'.

   (c) 2008 Fair Isaac Corporation
       author: S. Heipcke, Aug. 2002
*******************************************************!)

model "Burglar 2" 
 uses "mmxprs"

 declarations
  ITEMS: set of string           ! Set of items
  WTMAX = 102                    ! Maximum weight allowed
  VALUE: array(ITEMS) of real    ! Value of items
  WEIGHT: array(ITEMS) of real   ! Weight of items
 end-declarations

 initializations from 'burglar.dat'
  VALUE
  WEIGHT
 end-initializations

(! alternatively:
 initializations from 'burglar2.dat'
  [VALUE, WEIGHT] as 'KNAPSACK'
 end-initializations
!)

 declarations
  take: array(ITEMS) of mpvar    ! 1 if we take item i; 0 otherwise
 end-declarations

! Objective: maximize total value
 MaxVal:= sum(i in ITEMS) VALUE(i)*take(i) 

! Weight restriction
 sum(i in ITEMS) WEIGHT(i)*take(i) <= WTMAX

! All variables are 0/1
 forall(i in ITEMS) take(i) is_binary  

 maximize(MaxVal)                 ! Solve the MIP-problem

! Print out the solution
 writeln("Solution:\n Objective: ", getobjval)
 forall(i in ITEMS)  writeln(" take(", i, "): ", getsol(take(i)))
end-model