thermo_add.py crashes with NumPy 2.x and OpenMDAO 3.42+

[Jhawk414]

ThermoAdd.compute() raises a TypeError at line 121 due to two breaking changes:

• OpenMDAO 3.42.0 stores scalar inputs as (1,) arrays instead of scalars

• NumPy 2.0 removed implicit float() conversion on 1-element arrays

The crash: W_other_out[self.idx_compo] += W_other_mix on line 121 causes the following TypeErrors:

TypeError: 'DESIGN.burner.mix_fuel.thermo_add' <class ThermoAdd>: Error calling compute(), only 0-dimensional arrays can be converted to Python scalars

  File "C:\Users\REDACTED_FILEPATH\pycycle\thermo\tabular\thermo_add.py", line 121, in compute
    W_other_out[self.idx_compo] += float(W_other_mix)
                                   ^^^^^^^^^^^^^^^^^^
TypeError: only 0-dimensional arrays can be converted to Python scalars

Fix: change line 121 in thermo_add.py to W_other_out[self.idx_compo] += W_other_mix.item()

Versions: om-pycycle 4.4.0, openmdao 3.42.0, numpy 2.4.2

[stefano2734]

New releases Numpy 2.4.3 and openMDao 2.4.3
Should be Equal or perhaps more to do here?

[Jhawk414]

I'm not sure I understand your question.

However, OpenMDAO release 3.43.0 was released today (11 March 2026) and I haven't had a chance to see if this issue is affected.

[stefano2734]

I'm not sure I understand your question.

However, OpenMDAO release 3.43.0 was released today (11 March 2026) and I haven't had a chance to see if this issue is affected.

Sometimes new version errors are solved in next version. NumPy 2.44 is also now available.
And sometimes a permanent change is the source of failure.

[flight-test-engineering]

@Jhawk414 , are you going to open a PR with your fix?

[Jhawk414]

Yep. As shown I've created PR #117 to address this. One line fix