# Decision Optimization

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## Cplex 12:10 and Python

• #### 1.  Cplex 12:10 and Python

Posted Mon May 25, 2020 08:20 AM

Hey everyone,

I had the unfortunate idea of updating cplex in my computer, but after doing that I can't run any notebook using the docplex library. Everytime I tried the following error appears:

With cplex 12.8, it was working normally.

Any suggestions.

```---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-8-dd5ac9c2ee34> in <module>()
6 for i in range(2,3):
7     print(i)
----> 8     LB,runtimetotal,UB,FirstLB,gap,cnt,case,status = AvoidanceRelaxed(i,cp)
9     print('\n>>> MAIN')
10     print(i,LB,UB,runtimetotal,FirstLB,gap,cnt,case,status,file=d)

<ipython-input-7-cd16611bc907> in AvoidanceRelaxed(n, nps)
63         # z constraint
64         for (i,j) in P:
---> 65             model.add_constraint(xr0[(i,j)]*vy[(i,j)] - yr0[(i,j)]*vx[(i,j)] <= (1- z[(i,j)])*Mbin11[(i,j)])
66             model.add_constraint(xr0[(i,j)]*vy[(i,j)] - yr0[(i,j)]*vx[(i,j)] >= -z[(i,j)]*Mbin12[(i,j)])
67

3326         """
-> 3327         ct = self._add_constraint_internal(ct, ctname)
3328         return ct
3329

2811         check_trivial = self._checker.check_trivial_constraints()
2812         if self._prepare_constraint(ct, used_ct_name, check_for_trivial_ct=check_trivial):
-> 2813             self._post_constraint(ct)
2814             return ct
2815         elif ct is True or ct is False:

~\AppData\Roaming\Python\Python36\site-packages\docplex\mp\model.py in _post_constraint(self, ct)
2819
2820     def _post_constraint(self, ct):
-> 2821         ct_engine_index = self._create_engine_constraint(ct)
2822         self._register_one_constraint(ct, ct_engine_index, is_ctname_safe=True)
2823         return ct

~\AppData\Roaming\Python\Python36\site-packages\docplex\mp\model.py in _create_engine_constraint(self, ct)
2697         eng = self.__engine
2698         if isinstance(ct, LinearConstraint):
-> 2699             return eng.create_linear_constraint(ct)
2700         elif isinstance(ct, RangeConstraint):
2701             return eng.create_range_constraint(ct)

~\AppData\Roaming\Python\Python36\site-packages\docplex\mp\cplex_engine.py in create_linear_constraint(self, binaryct)
770         return self._make_cplex_linear_ct(cpx_lin_expr=cpx_linexp,
771                                           cpx_sense=binaryct.cplex_code(),
--> 772                                           rhs=num_rhs, name=binaryct.get_name())
773
774     def create_block_linear_constraints(self, linct_seq):

~\AppData\Roaming\Python\Python36\site-packages\docplex\mp\cplex_engine.py in _make_cplex_linear_ct(self, cpx_lin_expr, cpx_sense, rhs, name)
758         cpxnames = [name] if name else []
759
762

~\AppData\Roaming\Python\Python36\site-packages\docplex\mp\cplex_engine.py in fast_add_linear(cpx, lin_expr, cpx_senses, rhs, names, ranges)
129         cpxenv = cpx._env
130         with chbmatrix(lin_expr, cpx._env_lp_ptr, 0,
--> 131                        cpxenv._apienc) as (rmat, nnz):
133                     len(rhs), nnz, rhs, cpx_senses,

AttributeError: 'Environment' object has no attribute '_apienc'
```

------------------------------
Fernando Dias
------------------------------

• #### 2.  RE: Cplex 12:10 and Python

Posted Mon May 25, 2020 09:16 AM
Did you also update docplex? What version of docplex do you use?

------------------------------
Daniel Junglas
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• #### 3.  RE: Cplex 12:10 and Python

Posted Mon May 25, 2020 09:23 AM

I tried but apparently it didn't work.

The current version is 2.10.150

------------------------------
Fernando Dias
------------------------------

• #### 4.  RE: Cplex 12:10 and Python

Posted Tue June 21, 2022 09:21 AM
HI,

I'm experiencing a similar problem. I have been using V12.9 with a Python v 3.7.3 and all worked well. I upgraded to 12.10 and I now get a similar error.

Is there are fix to this issue?

Thanks

Ashley

------------------------------
Ashley Jones
------------------------------

• #### 5.  RE: Cplex 12:10 and Python

Did you run `python [path-to-COS12.10-install]/python/setup.py install` already?
If doing so doesn't solve the issue, please let us know your Python version, and the versions of the `cplex` and `docplex` packages in your Python environment.