Originally posted by: SystemAdmin

Hello,

I was unable to load the CPLEX Python API. It complains that there is an undefined symbol in pycplex121.so.

% python
Python 2.5.2 (r252:60911, Jan 20 2010, 23:14:04) 
[GCC 4.2.4 (Ubuntu 4.2.4-1ubuntu3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cplex
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/net/dorsal/apps/ilog/cplex121/python/x86-64_debian4.0_4.1/cplex/__init__.py", line 149, in <module>
    import callbacks
  File "/net/dorsal/apps/ilog/cplex121/python/x86-64_debian4.0_4.1/cplex/callbacks.py", line 47, in <module>
    from _internal._aux_functions import apply_freeform_two_args, apply_freeform_one_arg
  File "/net/dorsal/apps/ilog/cplex121/python/x86-64_debian4.0_4.1/cplex/_internal/__init__.py", line 19, in <module>
    import _list_array_utils
  File "/net/dorsal/apps/ilog/cplex121/python/x86-64_debian4.0_4.1/cplex/_internal/_list_array_utils.py", line 13, in <module>
    import _pycplex as CPX
  File "/net/dorsal/apps/ilog/cplex121/python/x86-64_debian4.0_4.1/cplex/_internal/_pycplex.py", line 22, in <module>
    import pycplex121
ImportError: /net/dorsal/apps/ilog/cplex121/python/x86-64_debian4.0_4.1/cplex/_internal/pycplex121.so: undefined symbol: Py_InitModule4

I also tried to build the API under Python 2.6, but ran into the same problem.

I am using Ubuntu Linux 8.04 (hardy) on x86_64.

Thanks,
Carol
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Originally posted by: SystemAdmin

What version of Python did you use when the problem occurred?
For the Python API in CPLEX 12.1 you need Python 2.4. Python 2.5 or 2.6 is not supported by CPLEX 12.1.
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Originally posted by: SystemAdmin

Note that CPLEX 12.2 is compatible to Python 2.5 and 2.6. So, either you install Python 2.4 on your system, or you wait a little bit until CPLEX 12.2 becomes available for academics. You will not have to wait very long...

Tobias
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Originally posted by: SystemAdmin

Errors of this type typically result from trying to load the 32-bit CPLEX Python module with a 64-bit version of python or vice versa. If you use the version of CPLEX built for 64-bit linux this problem should go away.

As Tobias mentioned earlier, you will still run into the issue that Python 2.5 is not supported with CPLEX version 12.1, so you will either have to wait for the availability of CPLEX 12.2 or get Python 2.4 on the machine where you want to run the CPLEX Python API.

Philip Starhill
CPLEX Research Engineer
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Originally posted by: SystemAdmin

Actually, looking more closely at your error messages I see that you are using 64-bit CPLEX. I suspect that the Python runtime you are using is a 32-bit version, even though your system is 64-bit.

Philip Starhill
CPLEX Research Engineer
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Originally posted by: SystemAdmin

Thank you for your timely response. It was indeed due to the incompatibility between CPLEX 12.1 and Python 2.5. We installed CPLEX 12.2 and the Python API is now working.

Sorry it took me a while to report back. We purchased a "always current" license from ILOG a while ago, and we had to jump through some hoops with the IBM Customer Service to get the version 12.2 download.

Thanks,
Carol
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#DecisionOptimization