Decision Optimization

# the following code doesn't working, mysteriously
cpx.linear_constraints.add(
    lin_expr=[cplex.SparsePair(shipment[i,j,:,t].tolist() +[duration_p[i,j,t]],
      [1]*len(market) + [-vaData.max_cap[i]*vaData.max_pen])
      for i in range(len(plant))
      for j in range(len(prog))
      for t in range(len(time))],
    senses=["L"] * len(rownames),
    rhs=[0] * len(rownames),
    names=rownames)

The error msg for the first code snippet is " ValueError: (' invalid matrix input type -- ', 331044)". 
I also tried the following. 

cpx.linear_constraints.add(
    lin_expr=[cplex.SparsePair(np.append(shipment[i,j,:,t], duration_p[i,j,t]).tolist(),
      [1]*len(market) + [-vaData.max_cap[i]*vaData.max_pen])
      for i in range(len(plant))
      for j in range(len(prog))
      for t in range(len(time))],
    senses=["L"] * len(rownames),
    rhs=[0] * len(rownames),
    names=rownames)
​

and this is working. However, in the meantime we have

np.append(shipment[i, j, :, t], duration_p[i, j, t]).tolist() == shipment[i,j,:,t].tolist() +[duration_p[i,j,t]]

>>> True

Can anyone gives an explanation why the first one is not working?

Regards

Hi Daniel, 
Thanks for the quick response. Following is the traceback info. 

ValueError                                Traceback (most recent call last)
<ipython-input-111-aec32d29074e> in <module>
      7     senses=["L"] * len(rownames),
      8     rhs=[0] * len(rownames),
----> 9     names=rownames)

~/Programs/anaconda3/lib/python3.7/site-packages/cplex/_internal/_subinterfaces.py in add(self, lin_expr, senses, rhs, range_values, names)
   1257             lin_expr, senses, rhs, range_values, names)
   1258         return self._add_iter(self.get_num, self._add,
-> 1259                               lin_expr, senses, rhs, range_values, names)
   1260
   1261     def delete(self, *args):

~/Programs/anaconda3/lib/python3.7/site-packages/cplex/_internal/_baseinterface.py in _add_iter(getnumfun, addfun, *args, **kwargs)
     39         """non-public"""
     40         old = getnumfun()
---> 41         addfun(*args, **kwargs)
     42         return range(old, getnumfun())
     43

~/Programs/anaconda3/lib/python3.7/site-packages/cplex/_internal/_subinterfaces.py in _add(self, lin_expr, senses, rhs, range_values, names)
   1183         if lin_expr:
   1184             with CPX_PROC.chbmatrix(lin_expr, self._cplex._env_lp_ptr,
-> 1185                                     0) as (rmat, nnz):
   1186                 CPX_PROC.addrows(self._env._e, self._cplex._lp, 0,
   1187                                  num_new_rows, nnz, rhs, senses,

~/Programs/anaconda3/lib/python3.7/contextlib.py in __enter__(self)
    110         del self.args, self.kwds, self.func
    111         try:
--> 112             return next(self.gen)
    113         except StopIteration:
    114             raise RuntimeError("generator didn't yield") from None

~/Programs/anaconda3/lib/python3.7/site-packages/cplex/_internal/_procedural.py in chbmatrix(lolmat, env_lp_ptr, r_c)
    153 def chbmatrix(lolmat, env_lp_ptr, r_c):
    154     """See matrix_conversion.c:Pylolmat_to_CHBmat()."""
--> 155     mat = Pylolmat_to_CHBmat(lolmat, env_lp_ptr, r_c)
    156     try:
    157         # yields ([matbeg, matind, matval], nnz)

~/Programs/anaconda3/lib/python3.7/site-packages/cplex/_internal/_procedural.py in Pylolmat_to_CHBmat(lolmat, env_lp_ptr, r_c)
    162
    163 def Pylolmat_to_CHBmat(lolmat, env_lp_ptr, r_c):
--> 164     return CR.Pylolmat_to_CHBmat(lolmat, env_lp_ptr, r_c)
    165
    166

~/Programs/anaconda3/lib/python3.7/site-packages/cplex/_internal/_pycplex.py in Pylolmat_to_CHBmat(lolmat, env_lp_ptr, py_row_col)
   1624
   1625 def Pylolmat_to_CHBmat(lolmat: 'PyObject *', env_lp_ptr: 'PyObject *', py_row_col: 'PyObject *') -> "PyObject *":
-> 1626     return _pycplex_platform.Pylolmat_to_CHBmat(lolmat, env_lp_ptr, py_row_col)
   1627
   1628 def free_CHBmat(HBMat: 'PyObject *') -> "void":

ValueError: (' invalid matrix input type -- ', 331044)
​

# the following code doesn't working, mysteriouslycpx.linear_constraints.add(    lin_expr=[cplex.SparsePair(shipment[i,j,:,t].tolist() +[duration_p[i,j,t]],      [1]*len(market) + [-vaData.max_cap[i]*vaData.max_pen])      for i in range(len(plant))      for j in range(len(prog))      for t in range(len(time))],    senses=["L"] * len(rownames),    rhs=[0] * len(rownames),    names=rownames)

cpx.linear_constraints.add(    lin_expr=[cplex.SparsePair(np.append(shipment[i,j,:,t], duration_p[i,j,t]).tolist(),      [1]*len(market) + [-vaData.max_cap[i]*vaData.max_pen])      for i in range(len(plant))      for j in range(len(prog))      for t in range(len(time))],    senses=["L"] * len(rownames),    rhs=[0] * len(rownames),    names=rownames)​

np.append(shipment[i, j, :, t], duration_p[i, j, t]).tolist() == shipment[i,j,:,t].tolist() +[duration_p[i,j,t]]>>> True