Alvise Sommariva
Universit`a degli Studi di Padova Dipartimento di Matematica
Matrici triangolari
Nell’implementazione dei metodi di Jacobi, Gauss-Seidel, SOR,
pu´
o servire l’estrazione di particolari matrici triangolari. Vediamone
degli esempi.
>> h e l p t r i u
TRIU Extract u p p e r tr ian gul ar part .
TRIU ( X ) is the u p p e r tr ian gul ar part of X . TRIU ( X , K ) is the elements on and above the K−th
diagonal of X .
K = 0 is the main diagonal , K > 0 is above the main diagonal and K < 0 is below the main diagonal . >> h e l p t r i l
TRIL Extract l o w e r tr ian gul ar part .
TRIL ( X ) is the l o w e r tr ian gul ar part of X . TRIL ( X , K ) is the elements on and below the K−th
diagonal of X .