Could someone please explain to me in fairly basic terms what the L2-norm is and what it does please. More specifically let me know what the following equation does, if possible... E(N) = 2*pi [tex]\int[/tex] (U(N) - Uexact)2 r dr Where E is the error for a specific N. Ultimately I have values for an approximation and exact values and want to do some sort of error analysis. I haven't found any good resources for learning about this on the internet. Also if someone could recommend a good book that would be great. Thanks in advance!