function [y] = rms2(v)
% rms Root mean square
% rms(v) returns the root mean square of the 
% elements of the column vector v. If v is a matrix, 
% then rms(v) returns a row vector such that each element
% is the root mean square of the elements in the corresponding
% column of v.
% BJ Furman
% 14NOV2009

vs = v.^2;   % what does this line do? Also note semicolon.
s = size(v);
y = sqrt(sum(vs)/s(1));