Originally posted by: memop

Hi. I have a nonlinear model with division constraints. But OPL gives an error message: Function operator (..) not avaliable in content CPLEX. I have searched this problem in the forum, but neither solution is not applicable for my model. The code is as follows. How would you suggest a solution way to overcome this problem? Thank you very much in advance. 

{code}

{code}

#DecisionOptimization
#OPLusingCPLEXOptimizer

Hi,

have you tried to use CPO ?

For that you should turn

dvar float+ SCV_d[s in stations];

dvar float+ SCV_a[s in stations];

dvar float+ SCV_e[s in stations];

dvar float+ W_q[s in stations];

dvar float+ CT[s in stations];

dvar float+ WIP[s in stations];

dvar float+ TH[s in stations];

into dexpr float.

The keyword is

using CP;

in order to use CPO.

 

Regards

 

PS: see https://www.ibm.com/developerworks/community/forums/html/topic?id=5df70337-cf79-4328-871e-df80e570d4e2&ps=25

#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: memop

Thank you alex for your reply. I have tried to use CPO and the model works very well. But the computation time could be long for medium and big data sets. I think I need to develop CP model by integrating any search strategy.

I want to improve the mathematical model of the problem as a comparision method with CP model. It is not possible to model this problem with this nonlinear structure by using CPLEX, is it? Do you think that CPO is sufficient to solve the problem? 

Regards.

#DecisionOptimization
#OPLusingCPLEXOptimizer

Hye,
I want to ask, my objective function is nonlinear. I used CP to solve it, but when I run the configuration of the file, the solution is not an optimal solution as in CPLEX.  How can I solve the nonlinear problem using CPLEX rather than CP? Here is my coding:

using CP;
int scale=1000;
{string} depot=...;
{string} customer=...;
{string} vehicle=...;
{string} node=...;
int N=card(customer);
int pr=...;
float dist[node][node]=...;
float fcost[depot]=...;
float D[customer]=...;
float R[customer]=...;
float VC[vehicle]=...;
float VD[depot]=...;
dvar boolean x[node][node][vehicle];
dvar boolean z[depot];
dvar boolean y[depot][customer];
dvar int u[customer][vehicle];
dvar int scaleQ[i in depot] in 0..240000;
dexpr float Q[i in depot]=scaleQ[i]/scale;

dexpr float facility=sum(i in node, j in node:j!=i, k in vehicle)x[i][j][k]*dist[i][j];
dexpr float travel=sum(i in depot)fcost[i]*z[i];
dexpr float setup=17*sum(i in depot, j in customer)(D[j]-R[j])*y[i][j]/Q[i];
dexpr float holdinginventory=(1/pr)*sum(i in depot)(Q[i]*pr - Q[i]*sum(j in customer)(D[j]+R[j])*y[i][j]);
dexpr float cost=travel + facility + setup + holdinginventory;

minimize cost;
subject to {
forall(j in customer) sum(i in node, k in vehicle)x[i][j][k]==1;
forall(k in vehicle) sum(i in depot, j in customer)x[i][j][k]<=1;
forall(k in vehicle) sum(i in node, j in customer:j!=i)D[j]*x[i][j][k]<=VC[k];
forall(i in node, k in vehicle) (sum(j in node)x[i][j][k])- (sum(j in node)x[j][i][k])==0;
forall(i in depot) sum(j in customer)D[j]*y[i][j]<=VD[i]*z[i];
forall(j in customer) sum(i in depot)y[i][j]==1;
forall(l in customer, j in customer, k in vehicle) u[l][k]-u[j][k]+N*x[l][j][k]<= N-1;
forall(i in depot, j in customer, k in vehicle) (sum(h in node)(x[i][h][k]+x[h][j][k]))-y[i][j]<=1;
}

------------------------------
Farahanim Misni
------------------------------

Original Message:
Sent: Fri June 19, 2020 03:55 AM
From: ALEX FLEISCHER
Subject: Re: Division operator not available in CPLEX

Hi,

have you tried to use CPO ?

For that you should turn

dvar float+ SCV_d[s in stations];

dvar float+ SCV_a[s in stations];

dvar float+ SCV_e[s in stations];

dvar float+ W_q[s in stations];

dvar float+ CT[s in stations];

dvar float+ WIP[s in stations];

dvar float+ TH[s in stations];

into dexpr float.

The keyword is

using CP;

in order to use CPO.

 

Regards

 

PS: see https://www.ibm.com/developerworks/community/forums/html/topic?id=5df70337-cf79-4328-871e-df80e570d4e2&ps=25

#DecisionOptimization

Can you please create a new question instead of reactivating a 5 year old question with a completely different model? Also add what you have tried to get rid of the problem. Maybe include the CP log that shows that the solution is not optimal or explain why a solution claimed optimal by CP is not optimal.

------------------------------
Daniel Junglas
------------------------------

Original Message:
Sent: Fri June 19, 2020 03:55 AM
From: Farahanim Misni
Subject: Re: Division operator not available in CPLEX

Hye,
I want to ask, my objective function is nonlinear. I used CP to solve it, but when I run the configuration of the file, the solution is not an optimal solution as in CPLEX.  How can I solve the nonlinear problem using CPLEX rather than CP? Here is my coding:

using CP;
int scale=1000;
{string} depot=...;
{string} customer=...;
{string} vehicle=...;
{string} node=...;
int N=card(customer);
int pr=...;
float dist[node][node]=...;
float fcost[depot]=...;
float D[customer]=...;
float R[customer]=...;
float VC[vehicle]=...;
float VD[depot]=...;
dvar boolean x[node][node][vehicle];
dvar boolean z[depot];
dvar boolean y[depot][customer];
dvar int u[customer][vehicle];
dvar int scaleQ[i in depot] in 0..240000;
dexpr float Q[i in depot]=scaleQ[i]/scale;

dexpr float facility=sum(i in node, j in node:j!=i, k in vehicle)x[i][j][k]*dist[i][j];
dexpr float travel=sum(i in depot)fcost[i]*z[i];
dexpr float setup=17*sum(i in depot, j in customer)(D[j]-R[j])*y[i][j]/Q[i];
dexpr float holdinginventory=(1/pr)*sum(i in depot)(Q[i]*pr - Q[i]*sum(j in customer)(D[j]+R[j])*y[i][j]);
dexpr float cost=travel + facility + setup + holdinginventory;

minimize cost;
subject to {
forall(j in customer) sum(i in node, k in vehicle)x[i][j][k]==1;
forall(k in vehicle) sum(i in depot, j in customer)x[i][j][k]<=1;
forall(k in vehicle) sum(i in node, j in customer:j!=i)D[j]*x[i][j][k]<=VC[k];
forall(i in node, k in vehicle) (sum(j in node)x[i][j][k])- (sum(j in node)x[j][i][k])==0;
forall(i in depot) sum(j in customer)D[j]*y[i][j]<=VD[i]*z[i];
forall(j in customer) sum(i in depot)y[i][j]==1;
forall(l in customer, j in customer, k in vehicle) u[l][k]-u[j][k]+N*x[l][j][k]<= N-1;
forall(i in depot, j in customer, k in vehicle) (sum(h in node)(x[i][h][k]+x[h][j][k]))-y[i][j]<=1;
}

------------------------------
Farahanim Misni
------------------------------


Original Message:
Sent: Fri June 19, 2020 03:55 AM
From: ALEX FLEISCHER
Subject: Re: Division operator not available in CPLEX

Hi,

have you tried to use CPO ?

For that you should turn

dvar float+ SCV_d[s in stations];

dvar float+ SCV_a[s in stations];

dvar float+ SCV_e[s in stations];

dvar float+ W_q[s in stations];

dvar float+ CT[s in stations];

dvar float+ WIP[s in stations];

dvar float+ TH[s in stations];

into dexpr float.

The keyword is

using CP;

in order to use CPO.

 

Regards

 

PS: see https://www.ibm.com/developerworks/community/forums/html/topic?id=5df70337-cf79-4328-871e-df80e570d4e2&ps=25

#DecisionOptimization