* 
* GAMS program for knapsack, med to maengder.
* Se ogsaa Wyndor-glass eksemplet for brug af to-dimensionelle tabeller
* David Pisinger
* 

$eolcom //
option iterlim=999999999,reslim=300,optcr=0.0,optca=0.0,solprint=OFF,mip=XPRESS;

SETS
	i1	'genstand1'      
                /i1,  i2,  i3,  i4,  i5/
	i2	'genstand2'      
                /i1,  i2,  i3,  i4,  i5/

PARAMETERS
	b	'max energi'
       / 25 /

        e1(i1)	'energi1'
      /	i1     12
	i2      7
	i3      8
	i4     11
	i5     15 /

        e2(i2)  'energi2'
      /	i1     12
	i2      4
	i3      6
	i4     13
	i5     14 /

        s1(i1)	'smag1'
      /	i1     13
	i2     12
	i3      7
	i4      8
	i5     10 /

        s2(i2)  'smag2'
      / i1     21
	i2      4
	i3     12
	i4      8
	i5     16 / ;

VARIABLES
 	 z  			'total smag som skal optimeres'
binary variables x1(i1)   	'beslutningsvariable'
binary variables x2(i2)   	'beslutningsvariable'

EQUATIONS
	smag  	'total smag'
	energi	'total energi' ;

smag   ..	z =E= sum(i1, s1(i1)*x1(i1)) + sum(i2, s2(i2)*x2(i2));
energi ..	sum(i1, e1(i1)*x1(i1)) + sum(i2, e2(i2)*x2(i2)) =L= b ;

MODEL knapsack /ALL/ ; 
knapsack.workspace=10;
SOLVE knapsack USING MIP MAXIMIZING z ;

DISPLAY z.L;  // value of the objective
DISPLAY x1.L;  // x1.L  : Level, i.e. result
DISPLAY x2.L;  // x2.L  : Level, i.e. result