# Ye Liu

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## Activity overview

Latest activity by Ye Liu
• Ye Liu commented,

Thanks Mario for you reply!  Did you know by any chance the approximation of normal distribution? I have been looking it up and found all of them involve division. Since Gurobi cannot divide decisi...

• Ye Liu created a post,

### How to calculate normal distribution CDF where the mean and variance is linear combination of decision variables?

Hi, I wanted to express a constraint where the reward is calculated as a normal distribution CDF, and the upper bound, mean, and variance are linear expressions of some decision variables. 1) PDF ...

• Ye Liu commented,

Hi Jaromił,  Thanks for responding! I tried the following but still didn't work        from gurobipy import *        def mycallback(model, where):            if where == GRB.Callback.MIPNODE:      ...

• Ye Liu commented,

Hi Jaromił, Thank you so much! Yes, you are right, I used the iis.ilp file to find out that I forgot to relax the bound to be negative infinite. One minor issue is that iis.ilp file cannot overwrit...

• Ye Liu commented,

Hi Jaromił, Thanks a lot for your solution! However, when I implemented the code, sometimes I have the following message: Encountered an attribute error. I don't know if I made a mistake somewhere:...

• Ye Liu commented,

Thank you so much, Jaromił! I tried all of your suggestions, and they are very helpful.  I still have one question:  Adjusting the MIPGap is very useful; I changed the gap to 0.2%. But still, there...

• Ye Liu commented,

Thank you so much,  Jaromił! I really appreciate your response! When I was trying to construct a minimal working example, I found out that I used a vector instead of a scaler for the coefficient fo...

• Ye Liu commented,

Jaromił, thank you so much for your answers, it worked! You really helped me move forward with my research project!!! One more question regarding your previous response on How do I model conditiona...

• Ye Liu commented,

Thank you so much, Jaromił!!! I redefine y_10 as a vector then it works! I thought the new value of y_10 will overwrite the previous value so that's why I only used one variable y_10 before.  The m...

• Ye Liu commented,

Thanks, Jaromił for answering this question! I tried what you suggested, the model is still not solvable when T=3 (it works when T=2). Here is the minimal reproducible example showing the issue: im...