Lower triangular part of matrix
(Quaternion and octonion overloadings of standard MATLAB® function)
Y = tril(X, K)
tril(X, K) extracts the lower triangular part of the matrix X. It is a straightforward overloading of the MATLAB® function of the same name implemented by a common mechanism for quaternion functions that can be computed by separate application of the MATLAB® function to each component of the quaternion array.