upper triangular matrix

(data structure)

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

Generalization (I am a kind of ...)

Specialization (... is a kind of me.)
strictly upper triangular matrix, .

See also lower triangular matrix, ragged matrix.

Note: For example

i 1776

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

Author: PEB


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Entry modified 17 December 2004.
HTML page formatted Mon Feb 2 13:10:40 2015.

Cite this as:
Paul E. Black, "upper triangular matrix", in Dictionary of Algorithms and Data Structures [online], Vreda Pieterse and Paul E. Black, eds. 17 December 2004. (accessed TODAY) Available from: