Dear lammps mailing list
I am trying to perform the python wrap for lammps for the 5/3/12 version of the distribution , but keep running into problems.
i follow all the steps in the manual and everything works great when i build using python setup.py build
and then install using sudo python setup.py install everything works great and i do get the lammps.py and _lammps.so files , but when i try to check it even for the serial version typing form the python interactive mode
>>>from lammps import lammps
>>> lmp = lammps()
i get the error:
OSError: Could not load LAMMPS dynamic library
and when i leave the python interactive mode
Exception AttributeError: “lammps instance has no attribute ‘lmp’” in <bound method lammps.del of <lammps.lammps instance at 0x2526e18>> ignored
now i have seen in the mailing list this post :
http://lammps.sandia.gov/threads/msg26397.html
regarding a similar problem with the serial version and was wondering if there is maybe a problem with the paralleled version ?
if not then maybe can you help me out building and installing the paralleled version , what further information do i need to provide you ?
Thank you so much in advance !
Tal
You should verify that the setup_serial.py install actually
put the _lammps_serial.so file in the right place in
the python you are running (which might not be the
python that root is running). On my box it is here:
/usr/local/lib/python2.7/site-packages
and the file should be executable. There should also
be a lammps.py and lammps*egg-info in that dir.
If it's all there, then the CDLL command in lammps.py
is failing. This part of the Python doc page is relevant:
Before using LAMMPS in a Python program, one more step is needed. The
interface to LAMMPS is via the Python ctypes package, which loads the
shared LAMMPS library via a CDLL() call, which in turn is a wrapper on
the C-library dlopen(). This command is different than a normal Python
"import" and needs to be able to find the LAMMPS shared library, which
is either in the Python site-packages directory or in a local
directory you specified in the "python setup.py install" command, as
described above.
The simplest way to do this is add a line like this to your .cshrc or
other shell start-up file.
setenv LD_LIBRARY_PATH
${LD_LIBRARY_PATH}:/usr/local/lib/python2.5/site-packages
and then execute the shell file to insure the path has been updated.
This will extend the path that dlopen() uses to look for shared
libraries.
Steve