Y = abs(X)
abs(X) returns the absolute value for each element of X.
If X is complex, abs(X) returns the complex modulus (magnitude):
abs(X) = sqrt(real(X).^2+imag(X).^2)
If X is a MATLAB string, abs(X) returns the numeric values of the ASCII characters in the string. The way the string prints changes; the internal representation does not.
abs(-5) = 5abs(3+4i) = 5abs('3+4i') = [51 32 43 32 52 105]
angle,setstr,sign,strings,unwrap
(c) Copyright 1994 by The MathWorks, Inc.