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What could be the cause of "ERROR: Unexpected exception while running model: 31704179198" in pyomo?

I get this error message whenever I try to run code that uses the .dae extension.

I've been getting this error on code for a problem I've been working on. Eventually, I ran code that I found online for a different problem and got the same error. This makes me think that it's some error with how I'm running the solver (ipopt) rather than the code itself

Here's a link to the code from GitHub that I'm getting an error message with: https://github.com/Pyomo/pyomo/blob/master/examples/dae/Optimal_Control.py

I've been evoking the solve with: pyomo solve --solver=ipopt filename.py

Solution

  • Most of the DAE examples come with a second Python script for running the model. Models formulated with Pyomo.DAE are meant to be run from Python scripts and not using the pyomo solve command line. The optimal control problem you're looking at can be solved by using the command 

    python run_Optimal_Control.py

    If you take a look at this file you'll see the syntax for applying a discretization scheme to the dynamic model, creating a solver object using the SolverFactory, solving the model, and plotting the results.