%ISDIAG Determine whether a matrix is diagonal.
%   ISDIAG(X) returns true if X is a diagonal matrix. Otherwise, 
%   it returns false.
%
%   See also ISTRIL, ISTRIU, ISBANDED, DIAG, TRIL, TRIU, BANDWIDTH.

%   Copyright 2013 The MathWorks, Inc.
%   Built-in function.