Function File: q = tril (q)

Function File: q = tril (q, k)

Function File: q = tril (q, k, 'pack')

Return a new quaternion matrix formed by extracting the lower triangular part of the quaternion q, and setting all other elements to zero. The second argument k is optional, and specifies how many diagonals above or below the main diagonal should also be included. Default value for k is zero. If the option "pack" is given as third argument, the extracted elements are not inserted into a matrix, but rather stacked column-wise one above other.