Question

I am having difficulty with getting a f2py compiled module work in Python.

I have a piece of software written in Fortran that compiles well on a Linux 64bit machine.
Further on F2Py compiles a Python module that uses Fortran bits as well.

Here is how the Python module is compiled:

f2py --fcompiler=gfortran -I"path-to-dir-with-mod-files" -c -m mod_landems mod_landem.f90

But once I want to import that module I get an error (in Ipython):

----> 1 import mod_landems
ImportError: ./mod_landems.so: undefined symbol: __nesdis_landem_module_MOD_nesdis_landem

To be honest I am confused with this error. Search did not help much so I need to ask you here: how can I possibly make it work? If I put the python module code in the same directory as where the mod files are it produces same error message.

Here is a piece of my (primitive) code:

module n_landem
implicit none

! INPUT VARIABLES
real(8) Angle
real(8) Sm_Content
real(8) Veg_Frac
real(8) Soil_Temp
real(8) Land_Temp
real(8) Snow_Depth
real(8) Frequency

! OUTPUT VARIABLES
real(8) Emis_H
real(8) Emis_V

contains

subroutine landem

  USE NESDIS_LANDEM_MODULE
  USE TYPE_KINDS, ONLY : fp

  call NESDIS_LandEM(Angle,Frequency,Sm_Content,Veg_Frac,Soil_Temp,Land_Temp,Snow_Depth,Emis_H,Emis_V)
end subroutine landem
end module n_landem

If I recall correctly some time ago this module was importable, but can’t seem to make it work on either debian64 installation or debian32bit computer.

Answer 1

in your f2py call, you have to pass the libraries you are linking explicitly with ‘-l’, the same you would pass it to your Fortran compiler (i.e. gfortran). Therefore, does

f2py -c --fcompiler=gfortran -I"path-to-dir-with-mod-files" --fcompiler=gfortran -I"path-to-dir-with-mod-files" -lNESDIS_LandEM_Module -m mod_landems mod_landem.f90 -m mod_landems mod_landem.f90

work for you ?

Best,
Max.