Unable to figure out ' invalid matrix input type -- ', u'1'

[varun7rs at gmail.com]

Hello Everyone, 

I am currently working on Cplex using Python API. I have a problem when I run the code. I keep getting this error about the invalid matrix input but I'm not able to figure out what it is. I would be grateful if any of you could help. My function is as below

def add_constraint(self, variables, coefficients, sense, rhs, name):
    self.prob.linear_constraints.add(
      lin_expr = [[ variables, coefficients ]],
      senses =    [sense],
      rhs =       [rhs],
      names =     [name] )



Traceback (most recent call last):
  File "RW10.py", line 569, in <module>
    main(sys.argv[1:])
  File "RW10.py", line 562, in main
    solveVNEProblem( phy_network, demands, args.output)
  File "RW10.py", line 116, in solveVNEProblem
    solver.add_constraint( varNames, varCoeffs, "E", 1.0, "Location_Constraints1{}".format( demand.demandID ) )
  File "RW10.py", line 26, in add_constraint
    names =     [name] )
  File "/opt/ibm/ILOG/CPLEX_Studio125/cplex/python/x86-64_sles10_4.1/cplex/_internal/_subinterfaces.py", line 1187, in add
    rmat = _C_HBMatrix(lin_expr, self._cplex._env_lp_ptr, 0, self._env.parameters.read.apiencoding.get())
  File "/opt/ibm/ILOG/CPLEX_Studio125/cplex/python/x86-64_sles10_4.1/cplex/_internal/_matrices.py", line 74, in __init__
    raise TypeError(" invalid matrix input type -- ", self._mat[0])
TypeError: (' invalid matrix input type -- ', u'1')


Thank You