Originally posted by: Crubal

Hi,

During writing the code, I want to define sets (described in the attachment); where I have the initial code:

int Resources = ...; // Number of Stations to select;
 range Stations = 1..Resources;
 float charge_stations[Stations];
  
 range Interchanges = 1..Resources; // Number of Interchanges to be covered;

 // Define Traffic Flow sets, distance and related binary variable
 tuple flow    {int i; int j;}
 setof(flow) Flows  = {<i,j> | ordered i,j in Interchanges};
 float distance_flow[Flows] = ...;
 
 
 tuple stations {
 float charge_stations; 
 }
 
 tuple traffic_flow {
 float distance_flow; 
 }

 float Budget;
 float Safety_distance;

 dvar int Build[Stations];
 dvar boolean FlowsInSet1[Flows];
 dvar boolean Cover[<i,j> in Flows];

Thanks a lot!

Originally posted by: Crubal

After someone's help, 

setof(flow) Flows_1 = {<i,j>| <i,j> in Flows: distance_flow[<i,j>] <= Safety_distance * 0.25};  is generated. 

However, I would like to add a station k where k is built in <i,j> (on the route of i and j). Can I define:

setof(flow) Flows_11 = {<i,k>| <i,k> in Flows_1: distance_flow[<i,k>]<= Safety_distance * 0.25};

Or how to combine the two conditions together?

Thanks!

Hi,

you could try to use arrays of sets:

range Flows=1..5;
 float Safety_distance=5;
 
 tuple flow
 {
 int o;
 int d;
 }
 
 {flow} s={<i,j> | i,j in Flows: i!=j};
 
 float distance_flow[i in s]=pow(i.d-i.o,2);

 setof(flow) Flows_1 = {i| i in s: distance_flow[i] <= Safety_distance * 0.25};
 
 
 setof(flow) Flows_11[i in Flows_1] = {<i.o,k>| <i.o,k> in Flows_1: distance_flow[<i.o,k>]<= Safety_distance * 0.25};
 execute
 {
 writeln(Flows_1);
 writeln(Flows_11);
 }

regards

Originally posted by: Crubal

Thank you Alex,

Can I ask 

float distance_flow[i in s]=pow(i.d-i.o,2);

setof(flow) Flows_11[i in Flows_1] = {<i.o,k>| <i.o,k> in Flows_1: distance_flow[<i.o,k>]<= Safety_distance * 0.25};

What do they mean?

Thanks!

Hi,

maybe you could spend some time having a look at our documentation and http://www-01.ibm.com/support/docview.wss?uid=swg21647915

float distance_flow[i in s]=pow(i.d-i.o,2);

means that the distance is computed as the square of the difference between origin o and destination d

setof(flow) Flows_11[i in Flows_1] = {<i.o,k>| <i.o,k> in Flows_1: distance_flow[<i.o,k>]<= Safety_distance * 0.25};

is for each element i in Flows_1 the set of all arcs <o,k> starting at i such as the distance flow of <o,k> is less than 0.25 times the safety distance

regards

Originally posted by: Crubal

Hi Alex,

Thank you! I will take a look at the documentation, and I really appreciate your help!