[HELP] Sensitivity analysis

Answered

Evans Etrue Howard

March 22, 2021 14:17

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I have successfully solved this MIP in Gurobi. I tried performing a sensitivity analysis on the results but I get getting these errors:

print(mo.getAttr(GRB.Attr.Pi))

GurobiError: Unable to retrieve attribute 'Pi'

and 

print(mo.getAttr(GRB.Attr.RC))

GurobiError: Unable to retrieve attribute 'RC'

 

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  June 23, 2025 02:57 Edited

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
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  Jaromił Najman

  • Gurobi Staff

  March 22, 2021 14:30

  RC is a variable attribute and Pi is a constraint attribute. Thus, you have to access those via the particular objects, see getAttr() and Python Attribute Examples.

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  Evans Etrue Howard

  March 22, 2021 15:30

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  I tried and I still got this error message

   

  print(mo.getAttr("Pi", mo.getConstrs()))

   

  ---------------------------------------------------------------------------
  GurobiError                               Traceback (most recent call last)
  <ipython-input-57-aeeada5b4371> in <module>
  ----> 1 print(mo.getAttr("Pi", mo.getConstrs()))
  
  src\gurobipy\model.pxi in gurobipy.Model.getAttr()
  
  src\gurobipy\attrutil.pxi in gurobipy.__gettypedattrlist()
  
  GurobiError: Unable to retrieve attribute 'Pi'

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  Jaromił Najman

  • Gurobi Staff

  March 22, 2021 19:03

  The Pi attribute is only available for continuous problems, cf. the documentation. For MIPs, see How do I retrieve the (dual) Pi values for a MIP problem?

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