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

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