Or-tools: "ModuleNotFoundError: No module named _pywraplp" after installing ortools binary via pip

[mwdickerson2016]

Hello,

I have successfully installed ortools via pip, with compatible versions of Python (3.6.3, 64-bit) and pip (9.0.1).

When I call "python my_program.py" to test the sample python code on this webpage: https://developers.google.com/optimization/introduction/run_programs

I get the following error message:
ModuleNotFoundError: No module named '_pywraplp'.

I've been struggling with this, so if anyone can remedy the problem, that would be great!

Thanks!

[Mizux]

Hi,
Did you only have this line ?

pywraplp.py is a python linear_solver which wrap _pywraplp.so library which is linked with libortools.so

I reproduce this kind of error having _pywraplp.so with incorrect link...
To verify if _pywraplp is correctly link:

$> pip show ortools
[...]
Location: /usr/local/google/home/corentinl/.local/lib/python3.5/site-packages
$> cd /usr/local/google/home/corentinl/.local/lib/python3.5/site-packages/ortools/linear_solver
$> ldd _pywraplp.so
[...]
libortools.so => not found

Actually there is a libortools-3bbb0a68.so in .../site-packages/ortools/.libs/

Try to uninstall everything and reinstall ortools

• pip uninstall ortools (until you have the message "Cannot uninstall requirement ortools, not installed')
• sudo pip uninstall ortools (until you have the message "Cannot uninstall requirement ortools, not installed')
• pip show ortools should return an error (1)
• pip install --user ortools

Now ldd should return

$> cd .local/lib/python3.5/site-packages/ortools/linear_solver
$> ldd _pywraplp.so
[...]
libortools-3bbb0a68.so => [...]/./../.libs/libortools-3bbb0a68.so

note: You can also test everything is fine using python3 -c "import ortools.linear_solver.pywraplp"

[mwdickerson2016]

When I did the uninstall ortools and reinstall, I got the following:

C:\Users\markw_000\Documents>pip show ortools Name: ortools Version: 6.6.4656 Summary: Google OR-Tools python libraries and modules Home-page: https://developers.google.com/optimization/ Author: Google Inc Author-email: [email protected] License: Apache 2.0 Location: c:\users\markw_000\appdata\roaming\python\python36\site-packages Requires: protobuf, six

Also, I noted that there's no /.libs/ folder within /ortools/

[Mizux]

Hi again,

So you are on windows.
According to this https://github.com/google/or-tools/blob/master/tools/setup.py#L52
I would say libortools is not shipped with the windows python binary package, but i'm still new on the project, so I need to dig a little bit more and double check to confirm...
EDIT: on windows ortools is built as static and integrated in each _pywrapXXX that's why you don't have any libortools.dll, since library is built on linux with default visibility, there is no export macro -> only static link is working IMHO...

My best guess: Try to also install 'or-tools C++' windows installer and see what's happen...

BTW I will look at it, since we would like to have python package shipped with everything needed (not only wrapper to the libortools.dll/.so but a standalone package)

[Mizux]

seems related to #556. Should be fixed on head now

[Mizux]

Using v6.7 everything seems to work (using a VS2017 x64 prompt)

[Setup]

> set path
Path=...C:\python36-64;C:\python36-64\Scripts;...
> where python
C:\python36-64\python.exe
> python --version
Python 3.6.3
> python -c "import platform; print(platform.architecture())"
('64bit', 'WindowsPE')
> python -m pip list
no or-tools...
> python -m pip install ortools
...
Installing collected packages: ... ortools
Successfully installed ortools-6.7.4957 ...

Then create a file my_program.py containing code at https://developers.google.com/optimization/introduction/run_programs

> type my_program.py
from __future__ import print_function
from ortools.linear_solver import pywraplp

def main():
  solver = pywraplp.Solver('SolveSimpleSystem',
                           pywraplp.Solver.GLOP_LINEAR_PROGRAMMING)
  x = solver.NumVar(0, 1, 'x')
  y = solver.NumVar(0, 2, 'y')
  objective = solver.Objective()
  objective.SetCoefficient(x, 1)
  objective.SetCoefficient(y, 1)
  objective.SetMaximization()
  solver.Solve()
  print('Solution:')
  print('x = ', x.solution_value())
  print('y = ', y.solution_value())

if __name__ == '__main__':
  main()

Try running it:

> python my_program.py
Solution:
x =  1.0
y =  2.0

So for me, it solved with the version v6.7.
Feel free to open issue if needed

[sayonsom]

I installed OR-Tools using the installer that comes with PyCharm. I am using 6.8.5452 version of OrTools, but I still get the same error. Here's what I am trying to run:

from ortools.linear_solver import pywraplp
def main():
      # Instantiate a mixed-integer solver
      solver = pywraplp.Solver('NonRooftopPVAllocation',
                       pywraplp.Solver.CBC_MIXED_INTEGER_PROGRAMMING)

      # x and y are integer non-negative variables.
      x = solver.IntVar(0.0, solver.infinity(), 'x')
      y = solver.IntVar(0.0, solver.infinity(), 'y')

And here's the error I am getting:

    Traceback (most recent call last):
    File "C:\Users\..\PycharmProjects\..\..\lib\site-packages\ortools\linear_solver\pywraplp.py", line 14, in swig_import_helper
    return importlib.import_module(mname)
     File "C:\Users\,,\AppData\Local\Programs\Python\Python36\lib\importlib\__init__.py", line 126, in 
     import_module
     return _bootstrap._gcd_import(name[level:], package, level)
     File "<frozen importlib._bootstrap>", line 994, in _gcd_import
     File "<frozen importlib._bootstrap>", line 971, in _find_and_load
     File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
     File "<frozen importlib._bootstrap>", line 658, in _load_unlocked
     File "<frozen importlib._bootstrap>", line 571, in module_from_spec
     File "<frozen importlib._bootstrap_external>", line 922, in create_module
     File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
     ImportError: DLL load failed: The specified module could not be found.
     During handling of the above exception, another exception occurred:
     Traceback (most recent call last):
     File "<input>", line 1, in <module>
     File "C:\Program Files\JetBrains\PyCharm 2018.2.1\helpers\pydev\_pydev_bundle\pydev_umd.py", line 194, in runfile
     pydev_imports.execfile(filename, global_vars, local_vars)  # execute the script
     File "C:\Program Files\JetBrains\PyCharm 2018.2.1\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile
     exec(compile(contents+"\n", file, 'exec'), glob, loc)

[lperron]

Did you install visual studio redistributables ?

Are you using a 64 bit version of Python?
Laurent Perron | Operations Research | [email protected] | (33) 1 42 68 53
00

Le mar. 18 sept. 2018 à 17:56, Sayon [e-mail] a écrit :

I installed OR-Tools using the installer that comes with PyCharm. I am
using 6.8.5452 version of OrTools, but I still get the same error. Here's
what I am trying to run:

from ortools.linear_solver import pywraplp
def main():
# Instantiate a mixed-integer solver
solver = pywraplp.Solver('NonRooftopPVAllocation',
pywraplp.Solver.CBC_MIXED_INTEGER_PROGRAMMING)

  # x and y are integer non-negative variables.
  x = solver.IntVar(0.0, solver.infinity(), 'x')
  y = solver.IntVar(0.0, solver.infinity(), 'y')

And here's the error I am getting:

Traceback (most recent call last):
File "C:\Users\..\PycharmProjects\..\..\lib\site-packages\ortools\linear_solver\pywraplp.py", line 14, in swig_import_helper
return importlib.import_module(mname)
 File "C:\Users\,,\AppData\Local\Programs\Python\Python36\lib\importlib\__init__.py", line 126, in
 import_module
 return _bootstrap._gcd_import(name[level:], package, level)
 File "<frozen importlib._bootstrap>", line 994, in _gcd_import
 File "<frozen importlib._bootstrap>", line 971, in _find_and_load
 File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
 File "<frozen importlib._bootstrap>", line 658, in _load_unlocked
 File "<frozen importlib._bootstrap>", line 571, in module_from_spec
 File "<frozen importlib._bootstrap_external>", line 922, in create_module
 File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
 ImportError: DLL load failed: The specified module could not be found.
 During handling of the above exception, another exception occurred:
 Traceback (most recent call last):
 File "<input>", line 1, in <module>
 File "C:\Program Files\JetBrains\PyCharm 2018.2.1\helpers\pydev\_pydev_bundle\pydev_umd.py", line 194, in runfile
 pydev_imports.execfile(filename, global_vars, local_vars)  # execute the script
 File "C:\Program Files\JetBrains\PyCharm 2018.2.1\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile
 exec(compile(contents+"\n", file, 'exec'), glob, loc)

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[sayonsom]

Hello Iperron,

I am using Python v 3.6.0 64 bit. Can you share the link to the VS Redistributable package you are referring to?

[lperron]

https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads

choose 64 bit version.
Laurent Perron | Operations Research | [email protected] | (33) 1 42 68 53
00

Le mar. 18 sept. 2018 à 18:36, Sayon [e-mail] a écrit :

Hello Iperron,

I am using Python v 3.6.0 64 bit. Can you share the link to the VS
Redistributable package you are referring to?

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[st0ne-c0ld]

Hello all,

I have similar issue on cygwin. Module is there, but it can't import it for some reason...

$ pip3 show py3-ortools
Name: py3-ortools
Version: 5.1.4041
Summary: Google OR-Tools python libraries and modules
Home-page: https://developers.google.com/optimization/
Author: Google Inc
Author-email: [email protected]
License: Apache 2.0
Location: /home/user1/py_spool/lib/python3.6/site-packages
Requires: protobuf
Required-by:
(py_spool)
localhost ~/py_spool/lib/python3.6/site-packages/ortools/linear_solver
$ pip3 show ortools
localhost ~/py_spool/lib/python3.6/site-packages/ortools/linear_solver
$ python -m ortools.linear_solver.pywraplp
Traceback (most recent call last):
  File "/home/user1/py_spool/lib/python3.6/site-packages/ortools/linear_solver/pywraplp.py", line 18, in swig_import_helper
    return importlib.import_module(mname)
  File "/home/user1/py_spool/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named '_pywraplp'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/user1/py_spool/lib/python3.6/site-packages/ortools/linear_solver/pywraplp.py", line 21, in <module>
    _pywraplp = swig_import_helper()
  File "/home/Vavaev/py_spool/lib/python3.6/site-packages/ortools/linear_solver/pywraplp.py", line 20, in swig_import_helper
    return importlib.import_module('_pywraplp')
  File "/home/user1/py_spool/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named '_pywraplp'

[lperron]

We do not support cygwin. Have you installed the visual studio
redistributable libraries ?
Laurent Perron | Operations Research | [email protected] | (33) 1 42 68 53
00

Le lun. 15 avr. 2019 à 13:19, st0ne-c0ld [e-mail] a
écrit :

Hello all,

I have similar issue on cygwin. Module is there, but it can't import it
for some reason...

$ pip3 show py3-ortools
Name: py3-ortools
Version: 5.1.4041
Summary: Google OR-Tools python libraries and modules
Home-page: https://developers.google.com/optimization/
Author: Google Inc
Author-email: [email protected]
License: Apache 2.0
Location: /home/user1/py_spool/lib/python3.6/site-packages
Requires: protobuf
Required-by:
(py_spool)
localhost ~/py_spool/lib/python3.6/site-packages/ortools/linear_solver
$ pip3 show ortools
localhost ~/py_spool/lib/python3.6/site-packages/ortools/linear_solver
$ python -m ortools.linear_solver.pywraplp
Traceback (most recent call last):
File "/home/user1/py_spool/lib/python3.6/site-packages/ortools/linear_solver/pywraplp.py", line 18, in swig_import_helper
return importlib.import_module(mname)
File "/home/user1/py_spool/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "", line 994, in _gcd_import
File "", line 971, in _find_and_load
File "", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named '_pywraplp'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/home/user1/py_spool/lib/python3.6/site-packages/ortools/linear_solver/pywraplp.py", line 21, in
_pywraplp = swig_import_helper()
File "/home/Vavaev/py_spool/lib/python3.6/site-packages/ortools/linear_solver/pywraplp.py", line 20, in swig_import_helper
return importlib.import_module('_pywraplp')
File "/home/user1/py_spool/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "", line 994, in _gcd_import
File "", line 971, in _find_and_load
File "", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named '_pywraplp'

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