tril 12345 12300 23451 23450 X=34512 ri(Xx,2)=345 45123 45123 51234 51234 00000tl(Xk) 00000 i(Xx,-2)=30000b x;j≤+k 45000 0 j>i+k 5 200
tril = 5 1 2 3 4 4 5 1 2 3 3 4 5 1 2 2 3 4 5 1 1 2 3 4 5 X = 5 1 2 3 4 4 5 1 2 3 3 4 5 1 2 2 3 4 5 0 1 2 3 0 0 tril(X ,2) − = 5 1 2 0 0 4 5 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 tril(X , 2) + + = j i k x j i k b i j i j 0 tril(X,k)
triu <j+k triu(X, k) 0 i>j+k T=-triu(tril(ones(6, 6), 1), -1)+3*eyes(6, 6) H T=-diag(ones(5, 1)-1)+diag(2*ones(6, 1),0)-diag(ones(5, 1),1) T=toeplitz(2 -1; zeros(4, 1)12 -1; zeros(4, 1D
triu + + = i j k x i j k b i j i j 0 triu(X,k) T=-triu(tril(ones(6,6),1),-1)+3*eyes(6,6) T=-diag(ones(5,1)-1)+diag(2*ones(6,1),0)-diag(ones(5,1),1) T=toeplitz([2;-1;zeros(4,1)],[2;-1;zeros(4,1)])
Block structure Al=101112;131415;161718]; Al2=20;21;22];A13=[3031:3233:3435] A2l=404142;434445]:A2=50;51] A23=60616263] AF=[All Al2 Al3: A21 A22 A23 C=A(24,5:6)
Block structure A11=[10 11 12; 13 14 15;16 17 18]; A12=[20;21;22]; A13=[30 31;32 33;34 35]; A21=[40 41 42; 43 44 45];A22=[50; 51]; A23=[60 61;62 63]; A=[A11 A12 A13; A21 A22 A23]; C=A(2:4,5:6);