tril

Syntax

tril(X, [k=0])

Arguments

X is a matrix.

k is an integer.

Details

If k is not specified: return the lower triangular portion of matrix X.

If k is specified: return the elements on and below the k-th diagonal of X.

Examples

$ m=matrix(1 2 3, 4 5 6, 7 8 9);
$ m;

col1	col2	col3
1	4	7
2	5	8
3	6	9

$ tril(m);

col1	col2	col3
1	0	0
2	5	0
3	6	9

$ tril(m,1);

col1	col2	col3
1	4	0
2	5	8
3	6	9

$ tril(m,-1);

col1	col2	col3
0	0	0
2	0	0
3	6	0

Related function: triu