Decision Optimization

Decision Optimization

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  • 1.  Invalid Syntax for Constraint

    Posted 08/05/22 02:42 AM
    Edited by System Admin 01/20/23 04:13 PM
    Dear All,
    When I created a constraint in pycharm with cplex library, there is an error as follows.
    Could anyone tell me what should I do, please? Thank you in advance.
    import cplex
    from docplex.mp.model import Model

    mdl = Model(name='Marking Optimization')
    inf = cplex.infinity
    bigM= 1000000

    n = 2 

    p = [40,100] 
    c = [20,100]
    v = 3 
    w = 5 

    m = [1,3]


    y = mdl.integer_var(lb = 0, ub=inf, name='y')

    #constraint 15
    mdl.add_constraint(1 >= y*(n+1)*(2*v + 2*w)

    #constraint 16

    mdl.add_constraint(1 >= (y*1/m[i])*(p[i] + c[i] + 2*w) for i in range(n))
      File "C:/Users/pknu/Documents/Research/project/Marking Optimization.py", line 25
        mdl.add_constraint(1 >= (y*1/m[i])*(p[i] + c[i] + 2*w) for i in range(n))
          ^
    SyntaxError: invalid syntax

    Process finished with exit code 1

    #DecisionOptimization


  • 2.  RE: Invalid Syntax for Constraint

    Posted 08/05/22 06:29 AM
    Dear Nicholas,

    - constraints 15 has no closing parenthesis
    - to add multiple constrants use 'add_constraints'​ and pass a python sequence, not a generator.
    I hope this helps.

    Cheers,

    ------------------------------
    Renaud Dumeur
    ------------------------------



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