I have a LP problem with many variables that represent different things. One of my variables can assume negatives or positives values, according to the timeslice. Inside an expression(@expression) I would like to accumulate ONLY the values positives of this variable. My variable is **var_x**. In reality, I have other loops nested, but to make it simpler the general idea is to get something that looks like that :

```
for t in timeslice
if var_x[t]> 0
acc_x = @expression(model,acc_x + var_x[t] )
end
end
```

I have tried this idea but I got the following error :

```
ERROR: LoadError: MethodError: no method matching isless(::Int64, ::JuMP.Variable)
```

Anyone knows another way to compare variables JuMP? Thanks in advance.