Does it matter how you define the error in a numerical solution?

[thehoten]

Does it matter how you define the error in a numerical solution??

If you define the error as numerical solution - exact solution would you be hugely wrong even if you understood what was happening (i know it's the negative of exact - numerical). I wrote a report at uni and realized i defined the error in this way

 

[mathman]

Usually when talking about error, the magnitude is most important. The sign is only for clarity.

Typical presentation is V ± E, where V is the value and E is the error.