Anaerobic Digester Re-Scaling

[MarcusHolly]

Summary/Motivation:

Adds the new IDAES scaling routine (scaler objects) to the anaerobic digester unit model. This should be merged after #1519 and #1530 are merged in.

Changes proposed in this PR:

• Updates the scaling routine of the anaerobic digester
• Updates testing

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[adam-a-a]

Shouldn't these be handled in the scaler class?

[MarcusHolly]

Andrew mentioned that we should not mix and match the new and old scaling tools. In other words, the scaler class should not make use of iscale. This is the reason why I've moved all of the iscale.set_scaling_factor to the calculate_scaling_factors function (in this PR and in others), which won't be called when exclusively using the new scaling tools.

If your question is why don't I set these default scaling factors in the ADScaler class, it's because I figured these would make more sense as user-defined scaling factors. I know I did do some testing with having default scaling factors for these variables in the new scaler class, but I forget how thoroughly I played around with this. Currently, the only variable scaled by default in the new scaler class is volume.

[adam-a-a]

Would it make sense to check the condition number at the flowsheet level between old scaling approach and new?

[adam-a-a]

Then, every time another PR impacts scaling at this flowsheet level, we can track whether condition number improves or not as we go.

[MarcusHolly]

Noting that the ScalingProfiler cannot currently be applied to the AD unit model since the ADM1 and modified ADM1 reaction packages have potential divisions by zero (see def rule_I_pH_aa(self)).

[adam-a-a]

Noting that the ScalingProfiler cannot currently be applied to the AD unit model since the ADM1 and modified ADM1 reaction packages have potential divisions by zero (see def rule_I_pH_aa(self)).

Interesting note. What happens exactly? Does ScalingProfiler do some sort of check for potential division by zero beforehand and raise an exception, or do you get back some exception that occurred having to do with division by zero? It’d be good to elaborate on this.

[MarcusHolly]

Noting that the ScalingProfiler cannot currently be applied to the AD unit model since the ADM1 and modified ADM1 reaction packages have potential divisions by zero (see def rule_I_pH_aa(self)).

Interesting note. What happens exactly? Does ScalingProfiler do some sort of check for potential division by zero beforehand and raise an exception, or do you get back some exception that occurred having to do with division by zero? It’d be good to elaborate on this.

This is the traceback:

Traceback (most recent call last):
  File "C:\GitHub\watertap\watertap\watertap\unit_models\tests\profiler_sandbox_AD.py", line 187, in <module>
    output = main()
             ^^^^^^
  File "C:\GitHub\watertap\watertap\watertap\unit_models\tests\profiler_sandbox_AD.py", line 181, in main
    results = sp.report_scaling_profiles()
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\idaes\core\scaling\scaler_profiling.py", line 166, in report_scaling_profiles
    results = self.profile_scaling_methods()
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\idaes\core\scaling\scaler_profiling.py", line 152, in profile_scaling_methods
    results[case] = self.run_case(meth, **margs)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\idaes\core\scaling\scaler_profiling.py", line 246, in run_case
    manual = self._run_scenario(
             ^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\idaes\core\scaling\scaler_profiling.py", line 289, in _run_scenario
    self._apply_scaling(m, scaling_method, block_based=block_based, **kwargs)
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\idaes\core\scaling\scaler_profiling.py", line 281, in _apply_scaling
    scaling_method(c, **kwargs)
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\idaes\core\scaling\custom_scaler_base.py", line 505, in scale_constraint_by_nominal_derivative_norm
    value(
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\pyomo\common\numeric_types.py", line 382, in value
    tmp = obj(exception=True)
          ^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\pyomo\core\expr\base.py", line 118, in __call__
    return visitor.evaluate_expression(self, exception)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\pyomo\core\expr\visitor.py", line 1301, in evaluate_expression
    ans = visitor.dfs_postorder_stack(exp)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\pyomo\core\expr\visitor.py", line 936, in dfs_postorder_stack
    ans = self.visit(_obj, _result)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\pyomo\core\expr\visitor.py", line 1187, in visit
    return node._apply_operation(values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\mholl\miniconda3\envs\watertap\Lib\site-packages\pyomo\core\expr\numeric_expr.py", line 1124, in _apply_operation
    return result[0] / result[1]
           ~~~~~~~~~~^~~~~~~~~~~
ZeroDivisionError: float division by zero