Error with addVars
AnsweredHi,
In my code I get the following error;
File "src\gurobipy\model.pxi", line 2725, in gurobipy.gurobipy.Model.addVars
What can be done to fix this problem?
And this is my code;
from gurobipy import GRB,Model,quicksum #*
def Output(m):
# Print the result
status_code = {1:'LOADED', 2:'OPTIMAL', 3:'INFEASIBLE', 4:'INF_OR_UNBD', 5:'UNBOUNDED'} #this is how a 'dictionary'
#is defined in Python
status = m.status
print('The optimization status is ' + status_code[status])
if status == 2:
# Retrieve variables value
print('Optimal solution:')
for v in m.getVars():
print(str(v.varName) + " = " + str(v.x))
print('Optimal objective value: ' + str(m.objVal) + "\n")
def ModelBetterImplemented(fuelcost, maintanencecost, laborcost, opportunitycost, demand,
shortagecost, travelkm, traveltimeroute, traveltimevehicle, spoilagecost, spoilageamount,
vehiclecapacity, numofvehicles, maxhourvehicle, utility ):
# Create the model
model = Model('model')
# Set parameters
model.setParam('OutputFlag',True)
k = 3 #number of products
i = 14 #number of routes
v=7 #number of vehicles
# Add variables
x = model.addVars(k, i, lb=0, ub=GRB.INFINITY, vtype=GRB.CONTINUOUS,
name=["x_"+str(i+1)+","+str(j+1) for i in range (k) for j in range(i)])
s = model.addVars(k, i, lb=0, ub=GRB.INFINITY, vtype=GRB.CONTINUOUS,
name=["s_"+str(i+1)+","+str(j+1) for i in range (k) for j in range(i)])
F = model.addVars(i, lb=0, ub=GRB.INFINITY, vtype=GRB.CONTINUOUS,
name=["F_"+str(j+1) for j in range(i)])
# minimize cost
model.setObjective( quicksum( fuelcost*travelkm[i] for i in range (i) )
+ quicksum( maintanencecost*travelkm[i] for i in range (i))
+ quicksum( laborcost*traveltimeroute[i] for i in range (i))
+ quicksum( shortagecost*s[i][j] for i in range (k) for j in range(i))
+ quicksum( spoilagecost*spoilageamount[i][j] for i in range (k) for j in range(i))
+ quicksum( opportunitycost*(1-utility[v]) for v in range (v)), GRB.MINIMIZE)
# demand/capacity constraint
model.addConstrs( (quicksum( demand[i,j] for i in range (k) ) <= F[j]
for j in range(i)) <= vehiclecapacity)
# demand/order constraint
model.addConstrs( quicksum( x[i,j] + s[i,j] + spoilageamount[i,j] == demand[i,j]
for i in range(k) for j in range(i)))
#employee/vehicle constraint
# model.addConstr( 2*numofvehicles== numofemployees)
#utility constraint
model.addConstrs( utility[v] == traveltimevehicle[v]/ maxhourvehicle[v] for v in range(v))
# Optimize the model
model.optimize()
Output(model)
# print the LP file
model.write('model.lp')
# print the sol file
model.write('model.sol')
ModelBetterImplemented(fuelcost=2, maintanencecost=1, laborcost=10, opportunitycost=3, spoilagecost=4, shortagecost=4,
demand=[[20,35,30,40,45,50,20,25,27,15,20,35,30,40],
[10,35,130,78,45,40,23,25,27,56,23,35,56,40],
[50,45,30,40,45,50,20,25,25,13,23,45,45,76]],
travelkm=[200,305,540,670,230,370,286,470,430,435,234,567,348,346],
traveltimeroute=[6,7,6,5.6,8,6,7.4,6,6.8,7,5,8,7.3,6.2],
traveltimevehicle=[6,7,6,5.6,8,6,7.4,6,6.8,7,5,8,7.3,6.2],
spoilageamount=[[10,12,15,7,8,5,15,13,8,9,6,17,9,11],
[10,12,15,7,8,5,15,13,8,9,6,17,9,11],
[10,12,15,7,8,5,15,13,8,9,6,17,9,11]],
vehiclecapacity=2000,
numofvehicles=7,
maxhourvehicle=[16,16,16,16,16,16,14],
utility=[0.5,0.5,0.5,0.45,0.5,0.5,0.5])
Thank you.
0
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Official comment
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Gurobi Staff
This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support. -
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Hi Neda,
You need to define your loops differently. In several places you are using the same variable as iterator as well as range indicator, e.g.:
name=["x"+str(i+1)+","+str(j+1) for i in range (k) for j in range(i)]
[...]
model.setObjective(quicksum(fuelcost*travelkm[i] for i in range (i)) [...]You should use a different name to define the dimensions of your problem to avoid these issues, e.g.:
k = 3 #number of products
i = 14 #number of routes
v = 7 #number of vehiclesshould be:
products = 3
routes = 14
vehicles = 7Then you can still use i,j,k as iterator variables in your loops and your code is much more readable.
Cheers,
Matthias0 -
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Hi Matthias,
Thank you for your help. I fixed that error. However now I get the following error;
GurobiError: Unsupported type (<class 'gurobipy.gurobipy.TempConstr'>) for LinExpr addition argument
Can you help me with this?
Thanks.
from gurobipy import GRB,Model,quicksum #*
def Output(m):
# Print the result
status_code = {1:'LOADED', 2:'OPTIMAL', 3:'INFEASIBLE', 4:'INF_OR_UNBD', 5:'UNBOUNDED'} #this is how a 'dictionary'
#is defined in Python
status = m.status
print('The optimization status is ' + status_code[status])
if status == 2:
# Retrieve variables value
print('Optimal solution:')
for v in m.getVars():
print(str(v.varName) + " = " + str(v.x))
print('Optimal objective value: ' + str(m.objVal) + "\n")
def ModelBetterImplemented(fuelcost, maintanencecost, laborcost, opportunitycost, demand,
shortagecost, travelkm, traveltimeroute, traveltimevehicle, spoilagecost, spoilageamount,
vehiclecapacity, numofvehicles, maxhourvehicle, utility ):
# Create the model
model = Model('model')
# Set parameters
model.setParam('OutputFlag',True)
products = 3 #number of products
routes = 14 #number of routes
vehicles=7 #number of vehicles
# Add variables
x = model.addVars(products, routes, lb=0, ub=GRB.INFINITY, vtype=GRB.CONTINUOUS,
name=["x_"+str(i+1)+","+str(j+1) for i in range (products) for j in range(routes)])
s = model.addVars(products, routes, lb=0, ub=GRB.INFINITY, vtype=GRB.CONTINUOUS,
name=["s_"+str(i+1)+","+str(j+1) for i in range (products) for j in range(routes)])
F = model.addVars(routes, lb=0, ub=GRB.INFINITY, vtype=GRB.CONTINUOUS,
name=["F_"+str(j+1) for j in range(routes)])
# minimize cost
model.setObjective( quicksum( fuelcost*travelkm[i] for i in range (routes) )
+ quicksum( maintanencecost*travelkm[i] for i in range (routes))
+ quicksum( laborcost*traveltimeroute[i] for i in range (routes))
+ quicksum( shortagecost*s[i,j] for i in range (products) for j in range(routes))
+ quicksum( spoilagecost*spoilageamount[i][j] for i in range (products) for j in range(routes))
+ quicksum( opportunitycost*(1-utility[v]) for v in range (vehicles)), GRB.MINIMIZE)
# demand/capacity constraint
model.addConstrs( (quicksum( demand[i][j] for i in range (products) ) <= F[j]
for j in range(routes)) )
# demand/order constraint
model.addConstrs( quicksum( x[i,j] + s[i,j] + spoilageamount[i][j] == demand[i][j]
for i in range(products) for j in range(routes)))
#employee/vehicle constraint
# model.addConstr( 2*numofvehicles== numofemployees)
#utility constraint
model.addConstrs( utility[v] == traveltimevehicle[v]/ maxhourvehicle[v] for v in range(vehicles))
# Optimize the model
model.optimize()
Output(model)
# print the LP file
model.write('model.lp')
# print the sol file
model.write('model.sol')
ModelBetterImplemented(fuelcost=2, maintanencecost=1, laborcost=10, opportunitycost=3, spoilagecost=4, shortagecost=4,
demand=[[20,35,30,40,45,50,20,25,27,15,20,35,30,40],
[10,35,130,78,45,40,23,25,27,56,23,35,56,40],
[50,45,30,40,45,50,20,25,25,13,23,45,45,76]],
travelkm=[200,305,540,670,230,370,286,470,430,435,234,567,348,346],
traveltimeroute=[6,7,6,5.6,8,6,7.4,6,6.8,7,5,8,7.3,6.2],
traveltimevehicle=[6,7,6,5.6,8,6,7.4,6,6.8,7,5,8,7.3,6.2],
spoilageamount=[[10,12,15,7,8,5,15,13,8,9,6,17,9,11],
[10,12,15,7,8,5,15,13,8,9,6,17,9,12],
[10,12,15,7,8,5,15,13,8,9,6,17,9,11]],
vehiclecapacity=2000,
numofvehicles=7,
maxhourvehicle=[16,16,16,16,16,16,14],
utility=[0.5,0.5,0.5,0.45,0.5,0.5,0.5])0 -
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Hi Neda,
You just need to remove the quicksum from this set of constraints - you cannot sum up constraints:
model.addConstrs(
x[i, j] + s[i, j] + spoilageamount[i][j] == demand[i][j]
for i in range(products)
for j in range(routes)
)Cheers,
Matthias0 -
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