Hello

I m writing a simple farm profit maximization model. I wrote the simple form and I got the answer which means that the model works, but when I used set notation to define variables I got many Syntax errors. Below is the model. would you please help me? I cannot understand where is the problem.

option sysout=off;

sets

i "option" /p,b,s,d/

j "products" /c,l,m/

k "type of product" /1,2,3,4,5,6,7,8,9,10,11,12,13,14/;

Alias (i,ii,iii)

variables

z total farm profit

x(i,j,k) amount of produced bought sold or distributed of each type of crop livestock or manure;

parameters

y(k) profit of each crop type/

"1" 937.45

"2" 9712.7

"3" 1011.43

"4" 10156.57

"5" 1085.41

"6" 10600.44

"7" 1140.89

"8" 10933.34

"9" 1002.13

"10" 118.03

"11" 484.42

"12" 365.39

"13" 532.91

"14" 0

/

equations

OBJ

land1

land2

machin1

machin2

machin3

machin4

livestock1

livestock2

feeding1

feeding2

feeding3

feeding4

rotation1

rotation2

rotation3

rotation4

rotation5

disposal1

disposal2

disposal3

spreading1

spreading2

spreading3;

OBJ..z=E= sum(k, x(p,c,k)* y(k)) + 1849*x(p,l,1)+ 53854*x(p,l,2)- 258.5*x(b,c,1) - 258.5*x(b,c,2) - 205.7*x(b,c,9) +15.70*x(s,m,3) -3.374*x(d,m,1) - 6.90*x(d,m,2);

land1.. sum(k$ x(p,c,k) lt14 ,x(p,c,k))=L=400;

land2.. x(p,c,14)=L=23;

.

.

.

the errors show problem with the firm line of OBJ function!!

Thank you so much

## Syntax error

### Re: Syntax error

Hi

If you write x(p,c,k), you probably mean x("p", "c",k). If you want to use specific set elements in an expression, you should use it like shown.

Cheers

Renger

If you write x(p,c,k), you probably mean x("p", "c",k). If you want to use specific set elements in an expression, you should use it like shown.

Cheers

Renger

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Enjoy modeling even more: Read my blog on modeling at The lazy economist