# View of Constraints and Decision Variables in Pyomo

Operations Research Asked on November 17, 2021

I have just attempted to construct my first Pyomo model.

However, I was unable to locate any documentation that shows how to view constraints, decision variables.

As my model is big, I need to see that they are created and indexed correctly from time-to-time before proceeding further.

May I ask if anyone has chanced upon such documentation or have devised any ingenious method to do so within the confines of Python or Pyomo syntax?

Thank you!

After defining your model by putting the following statement in your code (wherever you want before or after solve command) your model with all the objects has been printed:

model.pprint()


If you like to print constraints or variables individually:

model.cons1.pprint()  # For entire ConstraintList
print(model.cons2[i].expr)  # For only one index of ConstraintList
model.write() # To write the model into a file using .nl format


Assuming that model is the model that you defined and cons1 and cons2 are two ConstraintsList in that model.

Answered by Oguz Toragay on November 17, 2021

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