# triu

## Purpose

Upper triangular part of a matrix.

## Synopsis

    u = triu(X)
    u = triu(X,k)

## Description

`triu(X)` is the upper triangular part of `X`.

`triu(X,k)` is the element on and above the `k`-th diagonal of `X`. `k = 0` is the main diagonal, `k > 0` is above the main diagonal, and `k < 0` is below the main diagonal.

## Examples

`triu(ones(4,4),-1) is`

        1    1    1    1
        1    1    1    1
        0    1    1    1
        0    0    1    1

## See Also

    diag, tril

(c) Copyright 1994 by The MathWorks, Inc.