Silke Horn

The huge gap means that the objective of the root relaxation (i.e., the optimal fractional solution) is far away from the best integer solution that has been found so far. In your log, I can see th...

Welcome to Gurobi! With the X attribute, you access the variable's value in the current solution. Note that the code first does m.optimize() to find the optimal solution. The /(x[i,j].x/) is then p...

Hi Roy, To debug issues like this, you could write the model to an LP file and inspect that. In the LP file, you can often see if something went wrong when building your constraints. Yes, it is rec...

Hi Santanu, Could you also share your LP file? Thanks,Silke

Hi, There are more than six feasible solutions but six optimal ones. To get multiple solutions, you can use the Solution Pool feature. I am not aware of any way to retrieve multiple solutions using...

Gurobi 8 only supports R up to version 3.5. (See here.) It may be possible to work around this by manually adjusting the paths in the package, but this is not supported. Gurobi 9 (scheduled for lat...

Gurobi does not yet offer pip install. (It's on the roadmap though.) You can install it with Anaconda or via the pysetup program in the Gurobi <installdir>/bin directory.

Actually, Python 3.7 should already be supported with Gurobi 8.1.1. See here. (You have been on the Mac page, but there is an equivalent one for Windows.)

There are a few things I find confusing: In your dictionary, the values are strings. Maybe you want them to be arrays of strings instead? Then you could also access the individual entries. E.g.: {...

In the line IPmod.addConstrs((y[i,j]==1)>>(p[i]*x[i,j]+p[j]-d[j]>0), name="Unit Penalty"+str(i)+","+str(j)) try ">=0" instead of ">0". (Strict inequalities are not supported.)