| Symbolic Math Toolbox | |
Syntax
triu(X) triu(X, K)
Description
triu(X) is the upper triangular part of X.
triu(X, K) returns an upper triangular matrix that retains the elements of X on and above the k-th diagonal and sets the remaining elements to 0. The values k=0, k>0, and k<0 correspond to the main, superdiagonals, and subdiagonals, respectively.
A = [ a, b, c ] [ 1, 2, 3 ] [ a+1, b+2, c+3 ]Then
triu(A) returns
[ a, b, c ] [ 0, 2, 3 ] [ 0, 0, c+3 ]
triu(A,1) returns
[ 0, b, c ] [ 0, 0, 3 ] [ 0, 0, 0 ]
triu(A,-1) returns
[ a, b, c ] [ 1, 2, 3 ] [ 0, b+2, c+3 ]
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