Python 2.7 sub process

Question

I have a python script that uses a package called flopy. My script generates a series of inputs to a fortran executable. Flopy writes these into text files and then calls the fortran executable, which uses the text files to run a model.

I'm using a mac (OSX) and I downloaded python 2.7 from python.org- ie I'm not using the Apple system version of python. The version of python I'm using is in Library/Frameworks/Python.Frameworks/

I can run my script if I call it from the Terminal window (by typing:

Python myscriptname.py

However if I run my script through IDLE (the version that came with python which I downloaded it) it returns an error:

Traceback (most recent call last):
  File "/Users/neilthomas/RotatedModel_v4_Tr_mfnwt.py", line 355, in <module>
    success, mfoutput = mf.run_model(silent=False, pause=False)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flopy/mbase.py", line 638, in run_model
normal_msg=normal_msg)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/flopy/mbase.py", line 1034, in run_model
stdout=sp.PIPE, stderr=sp.STDOUT, cwd=model_ws)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 710, in __init__
errread, errwrite)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1335, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory 

The file 'mfnwt' absolutely does exist. I'm sure I'm missing something obvious, but is there something I need to do to allow IDLE to run programs/subprocesses via the shell it uses? Thanks.

Answer 1

The problem here is that you have to identify the specific MODFLOW executable file you are calling ('mfnwt' in your case). I do the same with a MODFLOW 2000 file:

mf = flopy.modflow.mf.Modflow(modelname,namefile_ext='nam',version='mf2k',exe_name='/home/MODFLOW-and-related-codes/build-08/bin-windows/mf2k.exe')

In your case, you would do something similar, only replacing the version='mf2k' and exe_name=path to match where you are storing your MODFLOW file.

See the documentation for further details: https://modflowpy.github.io/flopydoc/mf.html