I am solving a optimization problem using a european electric grid with 9241 nodes. To do that I created a connectivity matrix and inserted it in an Excel file. Using code from smaller problems (less nodes), which takes the information from the Excel file to write a CPLEX matrix, I tried to apply it to this bigger problem and I get the following error:
Exception from IBM ILOG Concert: Can not read data from excel. PEGASE-9241data.dat /Teste 8:36-37 E:\Program Files\IBM\ILOG\CPLEX_Studio129\opl\oplide\workspace\Teste\PEGASE-9241data.dat OPL Problem Marker
Some important things to know:
- The Excel file is .xlsx
- I wrote the connectivity matrix into the Excel file using Matlab (worked for smaller problems)
When I try the same code with a smaller problem (3120 nodes) It works fine.
Model:
range n = 1..9241;
dvar boolean x[n];
dvar boolean y[n][n];
//Conectivity matrix
int A[n][n] =...;
//Vector ZIB
int z[n] =...;
//Objective Function
dexpr int total = sum (p in n) x[p];
minimize (total);
subject to {
forall (i in n)
sum (j in n)
(A[i][j]*x[j] +A[i][j]*z[j]*y[i][j]) >= 1;
forall (j in n)
sum(i in n)
A[i][j]*y[i][j] == z[j];
}
Data:
SheetConnection sheet("E:\\Program Files\\IBM\\ILOG\\CPLEX_Studio129\\opl\\oplide\\workspace\\Teste\\PEGASEmatriz9241.xlsx");
A from SheetRead(sheet,"matriz9241");
z from SheetRead(sheet,"zib9241");
I think you have a memory issue. I managed to run the scalable example
til n=7000
So in your case I would divide your square into 4 squares. Let me share the full model to do that.
First to write into the Excel file in order to let you test.
.mod
execute
{
// http://cwestblog.com/2013/09/05/javascript-snippet-convert-number-to-column-name/
function toColumnName(num) {
for (var ret = '', a = 1, b = 26; (num -= a) >= 0; a = b, b *= 26) {
ret = String.fromCharCode(parseInt((num % b) / a) + 65) + ret;
}
return ret;
}
// 1,1 => A1 1,4 => D1 2,27 => AA2
function convertR1C1toA1(r,c)
{
return(toColumnName(c)+r);
}
}
int n=4;
int cell[i in 1..n][j in 1..n]=i*j;
int cell1[i in 1..n div 2][j in 1..n div 2]=cell[i][j];
int cell2[i in 1..n div 2][j in n div 2+1..n]=cell[i][j];
int cell3[i in n div 2+1..n][j in 1..n div 2]=cell[i][j];
int cell4[i in n div 2+1..n][j in n div 2+1 ..n]=cell[i][j];
string sheetWriteString1;
string sheetWriteString2;
string sheetWriteString3;
string sheetWriteString4;
execute
{
sheetWriteString1=convertR1C1toA1(1,1)+":"+convertR1C1toA1(n/2,n/2);
writeln("sheetWriteString1=",sheetWriteString1);
sheetWriteString2=convertR1C1toA1(1,n/2+1)+":"+convertR1C1toA1(n/2,n);
writeln("sheetWriteString2=",sheetWriteString2);
sheetWriteString3=convertR1C1toA1(n/2+1,1)+":"+convertR1C1toA1(n,n/2);
writeln("sheetWriteString3=",sheetWriteString3);
sheetWriteString4=convertR1C1toA1(n/2+1,n/2+1)+":"+convertR1C1toA1(n,n);
writeln("sheetWriteString4=",sheetWriteString4);
}
.dat
SheetConnection s("f2.xlsx");
cell1 to SheetWrite(s,sheetWriteString1);
cell2 to SheetWrite(s,sheetWriteString2);
cell3 to SheetWrite(s,sheetWriteString3);
cell4 to SheetWrite(s,sheetWriteString4);
and then in order to read f2.xls
.mod
int n=...;
string sheetWriteString1=...;
string sheetWriteString2=...;
string sheetWriteString3=...;
string sheetWriteString4=...;
int cell1[i in 1..n div 2][j in 1..n div 2]=...;
int cell2[i in 1..n div 2][j in n div 2+1..n]=...;
int cell3[i in n div 2+1..n][j in 1..n div 2]=...;
int cell4[i in n div 2+1..n][j in n div 2+1..n]=...;
int cell[i in 1..n][j in 1..n]=
(i<=n div 2)?((j<=n div 2)?cell1[i][j]:cell2[i][j]):((j<=n div 2)?cell3[i][j]:cell4[i][j]);
assert forall(i,j in 1..n) cell[i][j]==i*j;
.dat
SheetConnection s("f2.xlsx");
n=4;
sheetWriteString1="A1:B2";
sheetWriteString2="C1:D2";
sheetWriteString3="A3:B4";
sheetWriteString4="C3:D4";
cell1 from SheetRead(s,sheetWriteString1);
cell2 from SheetRead(s,sheetWriteString2);
cell3 from SheetRead(s,sheetWriteString3);
cell4 from SheetRead(s,sheetWriteString4);