# Changing the evaluation level: eval_level

### 5.12.2 Changing the evaluation level: eval_level

When it evaluates expressions, the maximum number of recursions that Xcas will do it called the evaluation level. This is 25 by default, but you can change the default level with the eval box in the CAS configuration screen (see section 2.5.7).

The eval_level command will change the evaluation level for the current session.

- eval_level takes one optional argument:
  Optionally n, a positive integer.
- eval_level() returns the current evaluation level.
- eval_level(n) sets the evaluation level to n.

#### Example.

Input:

purge(a,b,c)
a:=b+1; b:=c+1; c:=3;

Input:

eval_level()

Output:

25

Input:

a,b,c

Output:

5,4,3

Input:

eval_level(1)
a,b,c

Output:

b+1,c+1,3

Input:

eval_level(2)
a,b,c

Output:

c+2,4,3

Input:

eval_level(3)
a,b,c

Output:

5,4,3

Input:

eval_level()

Output:

3