Please correct my code

回答済み

Zatul Sahwee

2023年03月31日 11:02

• 
• 

I have this code below. However when I'm running it says my mod.update() & my mod.optimal() are invalid syntax
Could you help me to debug this?

def paper_production(demand, costs, inventory_level, production_level):
    ##Declare model
    mod = gp.Model('paper_production')
    mod.setParam('OutputFlag', 0)
    mod.setParam('LogToConsole', 0)

    obj = None
    production = None
    emergency = None
    
    ## Declare variables
    x = [mod.addVar(lb=0, vtype=GRB.CONTINUOUS, name='x_{i}')for i in range (5)]
    y = [mod.addVar(lb=0, vtype=GRB.CONTINUOUS, name='y_{i}')for i in range (5)]
    s = [mod.addVar(lb=0, vtype=GRB.CONTINUOUS, name='s_{i}')for i in range (5)]
    x[0] = 4000
    
    ## Constraints
    mod.addConstr(x[0] == production_level_ex['start']) 
    mod.addConstr(500 + x[1] + y[1] - s[1]  == demand[1])
    mod.addConstr(500 + x[1] + y[1] - demand[1]  == s[1])
    mod.addConstr(s[1] + x[2] + y[2] - s[2]  == demand[2])
    mod.addConstr(s[2] + x[3] + y[3] - s[3]  == demand[3])
    mod.addConstr(s[3] + x[3] + y[4] - s[4]  == demand[4])
    mod.addConstr(x[4] == production_level_ex['end'])
    mod.addConstr(s[4] >= inventory_level_ex['end'])                                          
    
    ## Objective
    mod.setObjective(gp.quicksum(x[i]+(costs_ex['emergency']*y[i])+(costs_ex['increase']* max(0,x[i]-x[i-1]))+(costs_ex['decrease']*max(0,x[i-1]-x[i])) + (costs_ex['storage']*s[i]) + (costs_ex['penalty']*max(0,s[4]-inventory_level_ex['start'])), GRB.MINIMIZE
      
   ## Update model and optimize
    mod.update()
    mod.optimize()
                        
    return mod.objVal

    print(paper_production(demand_ex, costs_ex, inventory_level_ex, production_level_ex))

関連

• Syntax Error

0

• 

  Marika Karbstein

  • Gurobi Staff

  2023年03月31日 12:48

  Your code is not reproducible but there are some issues with your objective definition

  • some brackets ')' are missing
  • 'i' is not defined 
  • you need to model max via general constraints, see Model.addGenConstrMax()
    please also have a look into the following article which gives a general idea of How do I model logical and general expressions? – Gurobi Help Center

  0

サインインしてコメントを残してください。