error running example

[stas-g]

hi,

i have the following error when running an example provided with the potassco suite:

nfg@NI-CA-107962:~/clingo_guide/examples$ asprin base.lp preference2.lp
asprin version 3.1.1
Reading from base.lp ...
*** ERROR: (asprin): 'Control' object has no attribute 'builder'
UNKNOWN

i am running clingo version 5.5.0 on ubuntu (WLS2).

any help would be appreciated.
thank you,
stasia

[javier-romero]

Hi Stasia, asprin works with version 5.4 of clingo, not with the latest 5.5 version. If you install it with conda in a new environment, it should already install the right version of clingo.

[stas-g]

dear Javier,

thank you for your quick reply. unfortunately, even after following your advice, the error persists:

(asprin_env) nfg@NI-CA-107962:~/clingo_guide/examples$ conda list
# packages in environment at /home/nfg/anaconda3/envs/asprin_env:
#
# Name                    Version                   Build  Channel
_libgcc_mutex             0.1                 conda_forge    conda-forge
_openmp_mutex             4.5                       1_gnu    conda-forge
asprin                    3.1.1                      py_1    potassco
ca-certificates           2021.10.8            ha878542_0    conda-forge
cffi                      1.15.0                   pypi_0    pypi
clingo                    5.4.0            py39h3fd9d12_1    potassco
ld_impl_linux-64          2.36.1               hea4e1c9_2    conda-forge
libffi                    3.4.2                h9c3ff4c_4    conda-forge
libgcc-ng                 11.2.0              h1d223b6_11    conda-forge
libgomp                   11.2.0              h1d223b6_11    conda-forge
libstdcxx-ng              11.2.0              he4da1e4_11    conda-forge
libzlib                   1.2.11            h36c2ea0_1013    conda-forge
ncurses                   6.2                  h58526e2_4    conda-forge
openssl                   3.0.0                h7f98852_1    conda-forge
pip                       21.3.1             pyhd8ed1ab_0    conda-forge
pycparser                 2.20                     pypi_0    pypi
python                    3.9.7           hf930737_3_cpython    conda-forge
python_abi                3.9                      2_cp39    conda-forge
readline                  8.1                  h46c0cb4_0    conda-forge
setuptools                58.3.0           py39hf3d152e_0    conda-forge
sqlite                    3.36.0               h9cd32fc_2    conda-forge
tk                        8.6.11               h27826a3_1    conda-forge
tzdata                    2021e                he74cb21_0    conda-forge
wheel                     0.37.0             pyhd8ed1ab_1    conda-forge
xz                        5.2.5                h516909a_1    conda-forge
zlib                      1.2.11            h36c2ea0_1013    conda-forge
(asprin_env) nfg@NI-CA-107962:~/clingo_guide/examples$ asprin base.lp preference2.lp
asprin version 3.1.1
Reading from base.lp ...
*** ERROR: (asprin): 'Control' object has no attribute 'builder'
UNKNOWN

additionally, it was complaining:
AttributeError: module 'clingo' has no attribute 'ast'
which i fixed by including a line importing ast in the asprin executable...

best,
stas

[javier-romero]

Hi, I am not sure about why is it happening.
Are you sure that the system is using the right version of clingo?
Sometimes one has to write export PYTHONPATH= to have a clean setting.

And maybe also try with a new clean environment,
although I guess you have already tried this:
conda create -n other_asprin -c potassco asprin

[rkaminsk]

My guess is that the clingo 5.5 module is still imported from somewhere. You can inspect which modules are included from where by passing the -v option to python.

[stas-g]

yes, @rkaminsk Roland, you are quite right --- python is still using clingo 5.5:

(asprin_env) nfg@NI-CA-107962:~/clingo_guide/examples$ pip freeze
asprin==3.1.1
cffi==1.15.0
clingo==5.5.0.post3
pycparser==2.20
(asprin_env) nfg@NI-CA-107962:~/clingo_guide/examples$ clingo
clingo version 5.4.0
Reading from stdin

i uninstalled clingo via: pip uninstall clingo so now pip freeze doesn't show it but i can still load it from within python (!) and my initial code of asprin base.lp preference2.lp works. thanks you for your help both!