Dear Sahan,

As you have a division term in your equations, you always have to check that the denominator is different than zero.

You can solve your problem in two ways: by multiplying the denominator to the left-hand part of the equation or by adding a conditional in the equations that only execute the division when denominator is different than zero. 

First case:

Equation 1: V_W(i)*ROW_P=E=((Jw(i)+Js(i));

Second case:

Equation 1: V_W(i)=E=((Jw(i)+Js(i))/(ROW_P)$(ROW_P 0);

Try if that works

Regards,

Laura

Dear Dr. Laura,

I am really grateful to you for your kind reply. I have modified my GAMS code considering the above mentioned two scenarios. Unfortunately, similar kind of error is displayed. Anyway thank you Dr. Laura for your worthy answer this is one of the useful outcome and might be helpful for my future Optimization problems.

Best Wishes,

sahan 

Hello Sahan

have you tried adding a very small number to the denominators say 1.0e-4 to ensure that during runtime, they are not zero. I.e.

Equation 1: V_W(i)=E=((Jw(i)+Js(i))/(ROW_P+0.0001))

Equation 2: Sh(i)=E=(K(i)*2*r_o)/(D+0.0001)

Hope this helps.

Dear Aliyu,

I am really grateful to you for your answer. I have tried your suggestion and it is helpful for my other optimization problems. unfortunately, i am unable to overcome this error in my present model. Once again thanks for your suggestion.

Regards,

sahan

Dear Sahan

I think our suggestions would work. 

What other kind of errors do you get from the GAMS log? Are you sure that the division by zero is only in those equations? please check the whole program

It's very weird that the problem remains after you tried all these suggestions

Regards,

Laura

Dear Dr. Laura and Aliyu,

I am really grateful for your kind reply. Your suggestions are one of useful outcome to decipher my GAMS code. Thank you for your worthy answers.

Best Regards,

sahan

Can communicate error message by GAMS. I would suggest put conditional syntax to avoid division by zero. Are your providing proper initial guesses for the denominator variable?

Dear Vinay Amte,

Thank you for your kind reply. Fortunately i am able to solve my code with proper initial guess and bounds. In my other Optimization model i have given conditional syntax to avoid division by zero error. Once again i thank you for your kind suggestion.

Best Regards,

sahan

First, you have to check the term in your equation which consists of division form especially the denominator. It is possible that ROW_P or D change to zero during iteration course then then you can add small value to these variable to prevent division by zero. Second, you may check the set of algebraic equation that you used wether the algebraic matrix is singular or not. If the matrix is singular then its inverse will be divided by zero.

Hi, I have a multi objective model and robust optimization that I want to solve with lp metric and In the execution time GAMS displayed me error "Division by Zero" .

and I found that Decision variable become zero and then display error.

what should I do to solve this model ?