Decision Optimization

Originally posted by: trxw

Hi,

My first post and complete new in this CPLEX world!

I have a 2D integer array (OrdenDeEntrada[person][instant]) with values 1 or 0 that means if a person is working or not in an instant. I want to build an dexpr which returns the lowest value of the index where we can find the first "1", i.e. time where this person starts working. From another post I manage to build a similar issue but with the exit time (OrdenDeSalida[person][instant] ) but I cannto figure out how to do it for the starting time

dexpr int OrdenDeSalida[i in person] = max(t in instant) (CtaTrabajando[i][t]==1)*t;  // This is the exit order which works fine

dexpr int OrdenDeEntrada[i in person] = min(t in instant) ((CtaTrabajando[i][t]==1)*(t));  // Returns always 0 

Hi

does the range "instant" contain 0 ?

regards

Originally posted by: trxw

No 0. From 1 to 47

hi

min cannot work because you need 1 for the decision variable and not 0

let me an example that could help you

int N=10;
range instant = 1..N;
dvar boolean x[instant];

dexpr int OrdenDeSalida = max(t in instant) (x[t]==1)*t;  // This is the exit order which works fine
dexpr int OrdenDeEntrada = N+1-max(t in instant) ((x[t]==1)*(N+1-t));   

subject to
{
forall(i in instant) (x[i]==1) == (3<=i<=7);
}

execute
{
writeln(OrdenDeSalida);
writeln(OrdenDeEntrada);
}

which gives

7
3

regards

Originally posted by: trxw

In fact, I find quite hard to operate with this arrays. Maybe I have not defined the right data type or just my ignorance. What I mean is that I need as well to count the number of "1" ending in the CtaTrabajando[person][Instantes] when the last value of the array is 1 (i.e. if a person works on the last instant, I need to count how many "1" are in that last rotation, so how many consecutive "1" are there)

Example:  

CtaTrabajando[1][Instantes]: 1 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 1 1 1   Count should be 3

CtaTrabajando[2][Instantes]  1 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 1 1 0   Count should be 0

This is a dexpr so I could use it in a minimize staticLex (MaxTT-MinTT, LastRotation); 

Hope it's clear... Thanks so much

Originally posted by: trxw

Thank you so much. It works great!!