Jaromił Najman

By providing a MIP start, the optimization path changes which in some cases can lead to a performance degradation instead of an improvement.  You can see the different optimization paths in the dif...

The error means that you are trying to access your list \(\texttt{Y}\) at an undefined entry given as \(\texttt{i,j,k,d}\). In order to debug this issue, you should print the values of \(\texttt{i,...

Hi Erik, Why does the last values from the callback function report upper bound as 8.0 and best bound 6.0? It is possible that the callback was not synced yet and the solution is found so quickly...

Hi, The upcoming Gurobi version 11 will be able to explicitly handle nonlinear functions such as \(\log, \exp, ...\). We are planning on improving this feature in every upcoming release after v11. ...

i thought if i do multiply a binary variable that is 0 or 1 with another variable shouldn't give me non linear equation. i delete it and now it works correctly and i can now finish my project, tha...

You have terms vbk[i,j,0]*(c[i,j,1] * x[i,j]) where vbk and x are both optimization variables. Thus, you have a nonlinear term vbk * x.

In addition to setting Method=2 and NodeMethod=2, you also have to set Crossover=0. This avoids the computation of a basis solution at the end of the root node which automatically leads to the usag...

Hi Jake, I am not a Julia expert but I think that the Knowledge Base article How do I terminate Gurobi with SIGKILL? might give you an idea of how to handle the \(\texttt{GRBterminate}\) call prope...

Hi Elvin, For these particular constraints, you have to define your matrix to have T columns and T-1 rows, where T is the number of x variables. Then set the diagonal marix entries to -1 and the up...

Hi Hussein, It is not possible to retrieve the number of (discrete) variables removed by presolve during the optimization. However, you could implement a MESSAGE callback, where you scan for the st...