triu
Syntax
triu(X, [k=0])
Arguments
X is a matrix.
k (optional) is an integer.
Details
If k is not specified: return the upper triangular portion of matrix X.
If k is specified: return the elements on and above 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 |
triu(m);
col1 | col2 | col3 |
---|---|---|
1 | 4 | 7 |
0 | 5 | 8 |
0 | 0 | 9 |
triu(m,1);
col1 | col2 | col3 |
---|---|---|
0 | 4 | 7 |
0 | 0 | 8 |
0 | 0 | 0 |
triu(m,-1);
col1 | col2 | col3 |
---|---|---|
1 | 4 | 7 |
2 | 5 | 8 |
0 | 6 | 9 |
Related function: tril