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

   file burglar_rec.mos
   ````````````````````
   Use of records.
   
   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 that 
   data may also be given in the form of a single record, in this
   case the array 'I' which is populated with the data file 
   burglar_rec.dat.

   (c) 2008 Fair Isaac Corporation
       author: S. Heipcke, July 2006
*******************************************************!)

model "Burglar (records)"
 uses "mmxprs"
 
 declarations
  WTMAX = 102                    ! Maximum weight allowed
  ITEMS = {"camera", "necklace", "vase", "picture", "tv", "video", 
           "chest", "brick"}     ! Index set for items
  
  I: array(ITEMS) of record
   VALUE: real                   ! Value of items
   WEIGHT: real                  ! Weight of items
  end-record
  take: array(ITEMS) of mpvar    ! 1 if we take item i; 0 otherwise
 end-declarations

 initializations from 'burglar_rec.dat'
  I
 end-initializations

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

! Weight restriction
 sum(i in ITEMS) I(i).WEIGHT*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