# istriu

Checks if matrix is upper triangular.

## Syntax

* tf = istriu(M)

## Input argument

* M - a numeric array

## Output argument

* tf - logical: result of 'istriu'.

## Description

**istriu** returns an scalar logical if entry is upper triangular.

## Example

```matlab
A = eye(3, 3);
R = istriu(A)
R = istriu(A(:,1))
```

## See also

[isdiag](isdiag), [istril](istril).

## History

| Version | Description     |
| ------- | --------------- |
| 1.0.0   | initial version |

## Author

Allan CORNET
