# Mario Ruthmair

Gurobi Staff
• Total activity 149
• Last activity
• Member since
• Following 0 users
• Followed by 1 user
• Subscriptions 55

## Activity overview

Latest activity by Mario Ruthmair
• Mario Ruthmair created an article,

### How do I avoid an increase in memory consumption when querying solution attributes in Python?

In some situations, especially when dealing with very large models, we can observe a significant increase in memory consumption when retrieving solution attributes after optimization in Python. The...

• Mario Ruthmair commented,

Hi, It seems your status variable is a given list of constants, not a Gurobi variable, right?What exactly are model variables and what is given input data?It seems for example that diffCharge are m...

• Mario Ruthmair commented,

Hi Ye, Sorry, I am not too much into the theory of normal distributions. Regarding modeling divisions: Sometimes, the divisions can be reformulated such that they can be handled in Gurobi. For exam...

• Mario Ruthmair commented,

Hi Ye, Gurobi variables cannot be directly used in arbitrary math functions, you have to use general constraints to deal with non-linear/non-quadratic terms. You might need to re-formulate your fun...

• Mario Ruthmair commented,

Please take a closer look at the paper I mentioned before. The flow conservation constraints (6) are defined per customer and sum up all incoming flow minus all outgoing flow. The same thing applie...

• Mario Ruthmair commented,

First of all, you can safely remove the k index, since you visit each customer exactly once. You just limit the number of arcs going out of the depot by m. The capacity constraints 5.72 can be repl...

• Mario Ruthmair commented,

Hi, Ok, I understand now. You might be able to handle your product also for $n>2$ by introducing additional variables in the following way: x_1 * x_2 = y_2y_2 * x_3 = y_3...y_{n-1} * x_n = c Best r...

• Mario Ruthmair commented,

Hi, Gurobi can only deal with linear and quadratic terms, more complicated functions like the square root expression can only be approximated with general constraints. To use those you might need t...

• Mario Ruthmair commented,

Hi Charitha, Indicator constraints only allow linear constraints. What you could do is to introduce additional variables that model the binary products and use those new variables in your indicator...

• Mario Ruthmair commented,

Hi, Gurobi can only handle linear and quadratic constraints. There are ways to add more general constraints that are then reformulated (and potentially approximated). You wrote that x is a continuo...