Re: [Quantlib-users] Failed to import QuantLib library in python

[Luigi B. <lui...@gm...>]

Christofer,
    I suspect at this point you have broken pieces of installation lying
around from three different Python versions and interfering with your new
attempts.  I suggest you use virtualenv to create a clean environment and
work in that one.  It's a good practice anyway.

Whatever version of python3 you want to use, create a new work directory,
enter it in the terminal, and run:

python3 -m venv ql-env

this will create a new directory ql-env with a clean Python environment
(based on the version you used). You don't need to enter in the directory:
stay where you are.  To activate the new environment, run:

. ql-env/bin/activate


(notice the single dot at the beginning followed by a space - that's
actually a command).  Your shell prompt should now have a (ql-env) at the
beginning to show that you're in the new environment.  Now, when you use
python or pip (or python3 or pip3) you'll get the versions in the
environment. To check, you can try:

pip list

which should return only pip and setuptools and no other module (because
the new environment is clean).  Now finally try:

pip install QuantLib

which should hopefully work.  If it does, install into the environment the
other modules you need.

The new environment is only active in the shell you're using; any other
shell and program using Python will still use the default one.  Also, if
you exit the terminal and later you come back and want to work in the
environment, you'll have to repeat the "activate" step above.

Hope this helps,
    Luigi



On Thu, Aug 13, 2020 at 8:45 PM Christofer Bogaso <
bog...@gm...> wrote:

> Appears to me that installing Quantlib in Mac-Python3 is
> frustratingly difficult and there are many breakpoints.
>
> I reinstalled Python and QuantLib altogether. With the new installation -
>
> >>> import sys
>
> >>> sys.path
>
> ['', '/Library/Frameworks/Python.framework/Versions/3.6/lib/python36.zip',
> '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6',
> '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/lib-dynload',
> '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages',
> '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/setuptools-33.1.1-py3.6.egg']
>
> >>> import QuantLib
>
> Traceback (most recent call last):
>
>   File "<stdin>", line 1, in <module>
>
>   File
> "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/QuantLib/__init__.py",
> line 21, in <module>
>
>     from .QuantLib import *
>
>   File
> "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/QuantLib/QuantLib.py",
> line 13, in <module>
>
>     from . import _QuantLib
>
> ImportError: cannot import name '_QuantLib'
>
> And now it is failing with a new reason!!!
>
>
> On Thu, Aug 13, 2020 at 11:11 PM Luigi Ballabio <lui...@gm...>
> wrote:
>
>> From inside Python, try
>>
>> import sys
>> print(sys.path)
>>
>> The list you get should include /usr/local/lib/python3.8/site-packages,
>> where pip3 installed QuantLib.  If not, you might have some configuration
>> to do.
>>
>> On Thu, Aug 13, 2020 at 7:09 PM Christofer Bogaso <
>> bog...@gm...> wrote:
>>
>>> It would be better if I can load QuantLin with Python3.
>>>
>>> I failed to use some of the packages with Python2 (2.7.16) like
>>> matplotlib. Thanks,
>>>
>>> On Thu, Aug 13, 2020 at 8:09 PM Javid Ashraff <jav...@ya...>
>>> wrote:
>>>
>>>> I recall having the same problem in the past.  Try using pip install
>>>> rather than pip3 install.
>>>>
>>>> Regards,
>>>>
>>>> Javid
>>>>
>>>> On Thursday, 13 August 2020, 19:15:32 GMT+8, Christofer Bogaso <
>>>> bog...@gm...> wrote:
>>>>
>>>>
>>>> Thanks.
>>>>
>>>> I have reinstalled Python3 using brew. And then installed again the
>>>> QuantLib as below -
>>>>
>>>> pip3 install QuantLib-Python
>>>>
>>>> Requirement already satisfied: QuantLib-Python in
>>>> /usr/local/lib/python3.8/site-packages (1.18)
>>>>
>>>> Requirement already satisfied: QuantLib in
>>>> /usr/local/lib/python3.8/site-packages (from QuantLib-Python) (1.19)
>>>>
>>>> After that I tried to import the library within Python3, but failed.
>>>>
>>>> >>> import QuantLib as ql
>>>>
>>>> Traceback (most recent call last):
>>>>
>>>>   File "<stdin>", line 1, in <module>
>>>>
>>>> ModuleNotFoundError: No module named 'QuantLib'
>>>>
>>>> Any idea why is it failing?
>>>>
>>>> On Thu, Aug 13, 2020 at 4:36 PM Luigi Ballabio <
>>>> lui...@gm...> wrote:
>>>>
>>>> I don't think there is.  You'll probably have to remove the *build/bdist.macosx-10.15-x86_64/egg/
>>>> *directory.  To be sure you're not missing anything, you might also
>>>> run "pip uninstall QuantLib-Python" first, then look for anything related
>>>> to QuantLib in /usr/local/lib and its Python subdirectories.  Once you
>>>> clean them (but be careful to only clean stuff with "quantlib" in its
>>>> name), you can run "pip install" again.
>>>>
>>>> Luigi
>>>>
>>>>
>>>> On Thu, Aug 13, 2020 at 12:00 PM Christofer Bogaso <
>>>> bog...@gm...> wrote:
>>>>
>>>> Thanks Luigi. But, how can I clean that? Is there any specific syntax?
>>>>
>>>> On Thu, Aug 13, 2020 at 3:19 PM Luigi Ballabio <
>>>> lui...@gm...> wrote:
>>>>
>>>> Hello,
>>>>     from the fact the traceback starts from "
>>>> *build/bdist.macosx-10.15-x86_64/egg/"* and the fact it refers to
>>>> */usr/local/lib/libQuantLib.0.dylib,* it looks to me like it's
>>>> importing a version you tried to compile rather than the one you installed
>>>> with pip.  If that's the case, I'd try cleaning that one up.
>>>>
>>>> Hope this helps,
>>>>     Luigi
>>>>
>>>>
>>>> On Thu, Aug 13, 2020 at 11:35 AM Christofer Bogaso <
>>>> bog...@gm...> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I wanted to run QuantLib from my Python workplace, however failed to
>>>> import the library with below error -
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *>>> import QuantLibTraceback (most recent call last):  File "<stdin>",
>>>> line 1, in <module>  File
>>>> "build/bdist.macosx-10.15-x86_64/egg/QuantLib/__init__.py", line 24, in
>>>> <module>  File "build/bdist.macosx-10.15-x86_64/egg/QuantLib/QuantLib.py",
>>>> line 13, in <module>  File
>>>> "build/bdist.macosx-10.15-x86_64/egg/QuantLib/_QuantLib.py", line 7, in
>>>> <module>  File "build/bdist.macosx-10.15-x86_64/egg/QuantLib/_QuantLib.py",
>>>> line 6, in __bootstrap__ImportError:
>>>> dlopen(/Users/aa/Library/Caches/Python-Eggs/QuantLib_Python-1.16.1-py2.7-macosx-10.15-x86_64.egg-tmp/QuantLib/_QuantLib.so,
>>>> 2): Symbol not found:
>>>> __ZN8QuantLib10IborCouponC1ERKNS_4DateEdS3_S3_jRKN5boost10shared_ptrINS_9IborIndexEEEddS3_S3_RKNS_10DayCounterEb
>>>> Referenced from:
>>>> /Users/aa/Library/Caches/Python-Eggs/QuantLib_Python-1.16.1-py2.7-macosx-10.15-x86_64.egg-tmp/QuantLib/_QuantLib.so
>>>> Expected in: /usr/local/lib/libQuantLib.0.dylib in
>>>> /Users/aa/Library/Caches/Python-Eggs/QuantLib_Python-1.16.1-py2.7-macosx-10.15-x86_64.egg-tmp/QuantLib/_QuantLib.so*
>>>>
>>>> I used the syntax *pip install QuantLib-Python* when I installed
>>>> QuantLib, the installation appears to be successful.
>>>>
>>>> Any help will be highly appreciated.
>>>>
>>>> Thanks,
>>>> _______________________________________________
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>>>>
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>>>>
>>>