how can i negative all value in a matrix except diagonal?
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arian hoseini
le 11 Jan 2022
Modifié(e) : Stephen23
le 11 Avr 2022
13.333 5 0 5 3.3333 0
5 27.333 4 10 3.3333 5
0 4 17.846 0 3.8462 10
5 10 0 17.5 2.5 0
3.3333 3.3333 3.8462 2.5 16.346 3.3333
0 5 10 0 3.3333 18.333
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Stephen23
le 11 Jan 2022
Modifié(e) : Stephen23
le 11 Avr 2022
M = [13.333,5,0,5,3.3333,0;5,27.333,4,10,3.3333,5;0,4,17.846,0,3.8462,10;5,10,0,17.5,2.5,0;3.3333,3.3333,3.8462,2.5,16.346,3.3333;0,5,10,0,3.3333,18.333]
Method one: subtraction (square only):
A = diag(diag(M)) - M.*~eye(size(M))
Method two: indexing (more robust, should work for any size):
B = -M;
B(eye(size(M))==1) = diag(M)
Plus de réponses (1)
Jon
le 11 Jan 2022
Am = -(A - diag(diag(A))) + diag(diag(A))
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Jon
le 11 Jan 2022
You could also do it in two lines using
Am = -A
Am(1:7:end) = A(1:7:end)
For both approaches, thanks to earlier posts from @John D'Errico https://www.mathworks.com/matlabcentral/answers/393125-how-to-replace-the-diagonal-entries-of-a-square-matrix-with-entries-from-a-vectore-of-equal-length
and
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