(data structure)

**Definition:**
A *matrix* that is only defined at (i,j) when i < j.

**Generalization** (I am a kind of ...)

*upper triangular matrix*.

**See also**
*strictly lower triangular matrix*, *ragged matrix*.

*Note:
For example *

j | ||||
---|---|---|---|---|

i | - | 7 | 7 | 6 |

- | - | 1 | 1 | |

- | - | - | 8 | |

- | - | - | - |

* It may be more compactly represented in an array by storing entry (i,j) in location n(i-1) + j - i(i-1)/2 - i = (2n-i)(i-1)/2 - i + j ( 1-based indexing).*

Author: PEB

Go to the Dictionary of Algorithms and Data Structures home page.

If you have suggestions, corrections, or comments, please get in touch with Paul Black.

Entry modified 16 November 2016.

HTML page formatted Wed Mar 13 12:42:46 2019.

Cite this as:

Paul E. Black, "strictly upper triangular matrix", in
*Dictionary of Algorithms and Data Structures* [online], Paul E. Black, ed. 16 November 2016. (accessed TODAY)
Available from: https://www.nist.gov/dads/HTML/strictlyUpperTriangMat.html