crash: "ValueError: zero-size array to reduction operation fmax which has no identity"

[iancrossfield]

In a number of runs I've encountered the following error, which crashes the VULCAN run. Will try to diagnose.

...
Equilibrium calculation (Fastchem) finished.
S8_l_s not included in fastchem.
/home/exolab/vulcan/build_atm.py:533: RuntimeWarning: divide by zero encountered in double_scalars
  Hp[i] = kb*Tco[i]/(mu[i]/Navo*gz[i])
Input stellar spectrum from 2.0 to 700.0
Photodissociation threshold: 655.5
Using wavelength bins from 2.0 to 655.5
The stellar flux is interpolated onto uniform grid of 0.1 (<240.0 nm) and 2.0 (>=240.0 nm) and conserving 100.11 % energy.
/home/exolab/vulcan/op.py:2162: RuntimeWarning: invalid value encountered in multiply
  var.tau[j] += var.y[j,species.index(sp)] * atm.dz[j] * var.cross[sp] # only the j-th laye
Traceback (most recent call last):
  File "/home/exolab/vulcan/vulcan.py", line 177, in <module>
    solver.compute_flux(data_var, data_atm)
  File "/home/exolab/vulcan/op.py", line 2305, in compute_flux
    var.aflux_change = np.nanmax( np.abs(var.aflux-var.prev_aflux)[var.aflux>vulcan_cfg.flux_atol]/var.aflux[var.aflux>vulcan_cfg.flux_atol] )
  File "<__array_function__ internals>", line 180, in nanmax
  File "/home/exolab/anaconda3/lib/python3.9/site-packages/numpy/lib/nanfunctions.py", line 476, in nanmax
    res = np.fmax.reduce(a, axis=axis, out=out, **kwargs)
ValueError: zero-size array to reduction operation fmax which has no identity