MES
1
I need the number of z(s)>0 in “equation”.

But z(s) is a variable and is also part in other equations of the same model.

My first idea was the following (shorter version):

```
Equation .. sum( (s)$(z(s) > 0 ) ,1)
=l= card(VN);
```

But it leads to an error:

57 VAR operands relational or boolean

Is it possible to solve this without introducing a binary variable?

snigdh
2
Hi MES,

Can you please share the solution to your question, in case you have found it.

Best regards,

Snigdh

MES
3
I decided to use a binary variable instead, because I couldn’t find another solution.

z(s)=sum(zue, bV(s,zue) * zue(s))

with bV(s)=1 if zue has a value, bV(s)=0 else

and with zue > 0, which presents the value

therefore the sum in the equation is

```
sum(s, bV(s));
```