CODEWITHSUNDEEP
cplex
Natdanai I.
Natdanai I.

Reputation: 49

CPLEX:How to get dvar value that >0

I want to bring min value that >0 of these dvar int values (contain with -,0,+ value) (in constraints section) 


forall(r in request)

first_delivery[r] == minl(delivery_time[r][k][j]); that >0

How can I do this ?

Thank you very much.

Upvotes: 0

Views: 152

Answers (1)

Alex Fleischer
Alex Fleischer

Reputation: 10037

You can compute new decision variables to keep only the values that are more than 1 and then use min:

dvar int x[1..4];
dvar int x2[1..4]; // derive from x, if x positive then x else max of x+1
dvar int y;
dvar int M; 

subject to
{

x[1]==0;
x[2]==-6;
x[3]==4;
x[4]==5;

M==max(i in 1..4) x[i];

forall(i in 1..4) 
{
x[i]<=0 => x2[i]==M+1;
x[i]>=1 => x2[i]==x[i];
}

y==min(i in 1..4) x2[i];
}

execute
{
writeln("y=",y);
}

which gives

y=4

Upvotes: 1

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