Fix division by zero bug for cubes with only one line

[waldeland]

Fixes this bug:

from seismic_zfp.conversion import SegyConverter
import segyio
path_to_segy = 'MC3D-GH2001R02BP-3D-PSTM-FINAL-FAR-VOLUME-STACK.MIG_FIN.10249887981_0000139-0000679.SEGY'
segy = segyio.open(path_to_segy, ignore_geometry=True, strict=False)
il = segy.attributes(segyio.TraceField.INLINE_3D)
print('inlines:',set(il))
with SegyConverter(path_to_segy) as converter:
    converter.run(path_to_segy + '.zfp', bits_per_voxel=4)

Which gives the output:

inlines: {0}
SEG-Y file is unstructured and no geometry provided. Determining this may take some time...
Converting: In=MC3D-GH2001R02BP-3D-PSTM-FINAL-FAR-VOLUME-STACK.MIG_FIN.10249887981_0000139-0000679.SEGY, Out=MC3D-GH2001R02BP-3D-PSTM-FINAL-FAR-VOLUME-STACK.MIG_FIN.10249887981_0000139-0000679.SEGY.zfp
Traceback (most recent call last):
  File "/nr/bamjo/user/andersuw/.pycharm_helpers/pydev/pydevconsole.py", line 364, in runcode
    coro = func()
  File "<input>", line 16, in <module>
  File "/nr/project/common/Statoil-DELI/usr/andersuw/deli_standalone_2/venv_deli_2/lib/python3.10/site-packages/seismic_zfp/conversion.py", line 226, in run
    self.infer_geometry(seismic)
  File "/nr/project/common/Statoil-DELI/usr/andersuw/deli_standalone_2/venv_deli_2/lib/python3.10/site-packages/seismic_zfp/conversion.py", line 164, in infer_geometry
    self.geom = InferredGeometry3d(traces_ref)
  File "/nr/project/common/Statoil-DELI/usr/andersuw/deli_standalone_2/venv_deli_2/lib/python3.10/site-packages/seismic_zfp/utils.py", line 49, in __init__
    self.min_il, self.max_il, self.il_step = self.get_range(il_ids)
  File "/nr/project/common/Statoil-DELI/usr/andersuw/deli_standalone_2/venv_deli_2/lib/python3.10/site-packages/seismic_zfp/utils.py", line 56, in get_range
    return min(ids), max(ids), (max(ids) - min(ids)) // (len(ids) - 1)
ZeroDivisionError: integer division or modulo by zero

[da-wad]

Code change is fine, please add a test in tests/test_utils.py which will pass for the updated function and fail for the old version. (Just for this function, no need to make a single-inline 3D SEG-Y file)

[waldeland]

Code change is fine, please add a test in tests/test_utils.py which will pass for the updated function and fail for the old version. (Just for this function, no need to make a single-inline 3D SEG-Y file)

Done.

[da-wad]

Try again with InferredGeometry3d.get_range() @waldeland ... it's a static method of the InferredGeometry3d class so doesn't come in the same namespace as most of the functions in utils.

[da-wad]

Looks good now!