Decision Optimization

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  • 1.  How to iterate in 2-D array in CPLEX any alternate

    Posted Tue April 06, 2021 04:32 PM
    Hi,
    I want to model thesein figure in CPLEX OPL, but CPLEX does not give opportunity to iterate in the multidimensional arrays. Cst and Tst are binary matrices, and the idea is to only sum for non zero elements.
    How can I do this please.
    Cst = [0 0 1]
             [1 0 1]
             [0 1 0]



    ------------------------------
    Muhammad Usama
    ------------------------------

    #DecisionOptimization


  • 2.  RE: How to iterate in 2-D array in CPLEX any alternate
    Best Answer

    Posted Wed April 07, 2021 04:43 AM
    Hi

    range S=1..3;
range T=1..3;

int Cst[S][T] = [[0, 0 ,1],
         [1 ,0, 1],
         [0 ,1 ,0]];
         
dvar boolean x[S][T];

dvar int su; // sum all x such as Cst is 1

maximize su;
subject to
{
  su==sum(s in S,t in T:Cst[s][t]==1) x[s][t];
}   ​


    works fine and gives su=4



    ------------------------------
    [Alex] [Fleischer]
    [EMEA CPLEX Optimization Technical Sales]
    [IBM]
    ------------------------------

    Original Message


  • 3.  RE: How to iterate in 2-D array in CPLEX any alternate

    Posted Thu April 08, 2021 09:55 AM
    Thank you, I have another question
    how can extract certain element from string set?
    basically I want to change index of an array to string set like
    v_1[{"a" "b"}][{"c" "d"}] = v[1..2][1..2]

    ------------------------------
    Muhammad Usama
    ------------------------------

    Original Message


  • 4.  RE: How to iterate in 2-D array in CPLEX any alternate

    Posted Thu April 08, 2021 10:06 AM
    Hi

    int v[1..2][1..2]=[[1,2],[3,4]];

{string} s1={"a", "b"};
{string} s2={"c", "d"};

int v1[i in s1][j in s2]=v[1+ord(s1,i)][1+ord(s2,j)];

execute
{
  writeln(v1);
}​

    gives

     [[1 2]
         [3 4]]


    ------------------------------
    [Alex] [Fleischer]
    [EMEA CPLEX Optimization Technical Sales]
    [IBM]
    ------------------------------

    Original Message


  • 5.  RE: How to iterate in 2-D array in CPLEX any alternate

    Posted Thu April 08, 2021 02:37 PM
    Thank you very much I has used loops to fill all arrays but this is so simple.
    another question is how to take intersection or union of two sets in constraints?
    like set Jp and and set Js
    Jp
    J1 J2 J3 J4
    P1     1  
    P2     1  
    P3     1  
    P4     1  
    P5     1  

    Js (Procesing Units)
    J1 J2 J3 J4
    S1 1 1 1 1
    S2 1 1 1  

    how can I implement ?

    ------------------------------
    Muhammad Usama
    ------------------------------

    Original Message


  • 6.  RE: How to iterate in 2-D array in CPLEX any alternate

    Posted Fri April 09, 2021 04:42 AM
    Edited by System Test Fri January 20, 2023 04:44 PM
    Hi,

    you can use inter

    In the documentation you have a small example:

    //This code line initializes rInter to {2}.


{int} i[1..3] = [ {1, 2}, {2, 3}, {2, 5} ]; 
{int} rInter = inter( x in 1..3 ) i[x];

​


    and with your values you could start with

    {int} P=asSet(1..5);
{int} J=asSet(1..4);
{int} Jp[p in P]={3};

assert forall(p in P) forall(x in Jp[p]) x in J;

{int} S={1,2};

{int} Js[S]=[{1,2,3,4},{1,2,3}];

int v[s in S][p in P]=sum(j in (Js[s] inter Jp[p])) i;

execute
{
  writeln(v);
}


    ------------------------------
    [Alex] [Fleischer]
    [EMEA CPLEX Optimization Technical Sales]
    [IBM]
    ------------------------------

    Original Message