Originally posted by: Fangxia H

Hi,everyone,

I use Java programming and  the version of  Cplex is 12.7.1.

I found that   using  eq() to  add equality constraint didn't work ,but addEq() did.

I wonder why this happens？

what difference between eq() and addEq() is?

From the reference documentation:

eq():

Creates and returns a range forcing the specified value to be equal to the specified numeric expression.

addEq():

Creates and returns a range initialized to represent the equality of the specified value and expression.

The range is added to the invoking model; that is, this method modifies the current model.

So, as you can see, the former only creates an object while the latter also adds that object to the model. I am not sure what you mean by "does not work" but I guess you mean that the equation is not added to the model. As you can see from the reference documentation, this is intended behavior.

Originally posted by: Fangxia H

Thanks, I mistakenly looked at the cplex reference documentation for the previous version. So I thought they were the same. Thanks again for your reply