Hello Everybody,

I am facing a problem with multiple set. i.e between m and p in the following command

My problem in short:

I have two machines, but want to produce three different products.

Each machine can produce only one product at a time. production time is 5 days.

2 machines - 3 products is the problem.

if it is 3 machine- 3 products… i would have produce each product in each machine separately.

pls chek the blue line. any suggestion for improvement. Thanks in Advance…

Set t time /1*20/
Set p product /1*3/

Set m machine /1*2/

Parameter Demand(t,p),Ordermin,Production,ptime;

Ordermin=50;

Demand(t,p) = normal(20,1);

Production=50;

ptime=5;

Variables Order(t,p), Startt(t,m), Endd(t,m), cumorder;

Binary variables b(t,p), Macstatus(t,m);

Equations Eq1(t,p,m), con1(t,p), Eq2(t,m), Eq3(t,p,m), Eq4(t,m), obj;

Eq1(t,p,m)… Order(t,p) =e= Order(t-1,p) + Demand(t,p) -Production*Endd(t,m);
con1(t,p)… Order(t,p) =l= Ordermin + 100000*b(t,p);

Eq2(t,m)… Macstatus(t,m) =e= Macstatus(t-1,m) + Startt(t-1,m) - Endd(t,m); Macstatus(t,m) = 0 (idle), 1( in-production)

Eq3(t,p,m)… Startt(t,m) =e= b(t,p)*(1-Machinestatus(t,m)); Startt(t,m)= 1(begining), 0 otherwise

Eq4(t,m)… Endd(t,m) =e= Startt(t-ptime,m); Endd(t,m) = 1(production finished), 0 otherwise

obj… cumorder =e= sum((t,p),Order(t,p));

Model productionn /all/;

OPTION OPTCR = 0.0, OPTCA = 0.0;

SOLVE productionn MINIMIZING cumorder USING MINLP ;

Display Demand,Order.L,Machinestatus.L,Startt.L,Endd.L,cumorder.L

Thanks

Swin

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