(!*******************************************************
   Mosel User Guide Examples
   =========================

   file knapsackr.mos
   ``````````````````
   Knapsack (sub)model of the for a paper cutting example,
   reading data from shared memory.
   Communication of data from/to parent model
   using 'shmem' IO driver with 'raw'.

   *** Not intended to be run standalone - run from paperpr.mos ***

   Solve the integer knapsack problem                              
     z = max{Cx : Ax<=B, x<=D, x in Z^N}  

   (c) 2008 Fair Isaac Corporation
       author: S. Heipcke, 2004, rev. July 2010
*******************************************************!)

model "Knapsack"
 uses "mmxprs"

 parameters
  NWIDTHS=5                            ! Number of different widths
 end-parameters
 
 declarations
  WIDTHS = 1..NWIDTHS                  ! Range of widths
  A,C: array(WIDTHS) of real           ! Constraint + obj. coefficients
  B: real                              ! RHS value of knapsack constraint
  D: array(WIDTHS) of integer          ! Variables bounds (demand quantities)
  KnapCtr, KnapObj: linctr             ! Knapsack constraint+objective
  x: array(WIDTHS) of mpvar            ! Knapsack variables
  xbest: array(WIDTHS) of integer      ! Solution values
 end-declarations
 
 initializations from "raw:noindex"
  A as "shmem:A" B as "shmem:B" C as "shmem:C"  D as "shmem:D"
 end-initializations
 
! Define the knapsack problem
 KnapCtr:= sum(j in WIDTHS) A(j)*x(j) <= B
 KnapObj:= sum(j in WIDTHS) C(j)*x(j)

! Integrality condition and bounds
 forall(j in WIDTHS) x(j) is_integer
 forall(j in WIDTHS) x(j) <= D(j)    ! These bounds can be omitted

 maximize(KnapObj)
 z:=getobjval
 forall(j in WIDTHS) xbest(j):=round(getsol(x(j)))

 initializations to "raw:"
  xbest as "shmem:xbest" z as "shmem:zbest"
 end-initializations

end-model