constraint with parameter that has variable as an index

Answered

mranalytics44

May 25, 2025 11:12

• 

i wanna add d[i, x[c, d]]     in an addConstrs() environment                 

d is defined as d[i, j] and is binary , the values are stored in a dict

x[c, d] is a variable of the model, it is an integer

I get this error: GurobiError: Variable has not yet been added to the model

 

thanks for helping!

 

Related to

• Model Building

0

• 

  Riley Clement

  • Gurobi Staff

  May 26, 2025 01:00

  Hi,

  This:

  d[i, x[c, d]]

  will not work.  Variables do not have a value until the model is solved, and so you cannot use their values as an index.

  I recommend dedicating the appropriate effort to learning the basics of mathematical modelling.  The following  Udemy course may interest you.

  https://www.udemy.com/course/intro-to-optimization-pt1/

  - Riley

  0

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