E=[] E = [] size(E) ans = 0 0 format compact zeros(3,2) ans = 0 0 0 0 0 0 zeros(3,0) ans = Empty matrix: 3-by-0 zeros(0,2) ans = Empty matrix: 0-by-2 rand(2,3) ans = 0.9501 0.6068 0.8913 0.2311 0.4860 0.7621 10*rand(2,3) ans = 4.5647 8.2141 6.1543 0.1850 4.4470 7.9194 round(10*rand(2,3)) ans = 9 2 9 7 4 9 round(10*rand(2,3))-5 ans = -1 -4 3 4 -1 -5 round(10*rand(2,3))-5 ans = -4 -3 -2 -3 1 -3 round(10*rand(4,5))-5 ans = -5 0 -3 2 2 2 -1 2 -1 -1 -1 3 3 3 -2 4 0 -5 0 -3 A=round(10*rand(4,5))-5 A = -3 -3 4 3 -2 2 2 1 1 -2 -2 -1 0 3 -2 0 4 4 2 0 A([1,3],[1,2,3]) ans = -3 -3 4 -2 -1 0 A([1,3],[1,2,4]) ans = -3 -3 3 -2 -1 3 A(:,[1,2,4]) ans = -3 -3 3 2 2 1 -2 -1 3 0 4 2 B=round(10*rand(2,3))-5 B = 2 3 -1 -2 1 2 C=round(10*rand(2,2))-5 C = 0 2 -1 1 [B,C] ans = 2 3 -1 0 2 -2 1 2 -1 1 D=round(10*rand(2,5))-5 D = 3 0 -3 -2 4 5 4 5 -2 2 [B,C;D] ans = 2 3 -1 0 2 -2 1 2 -1 1 3 0 -3 -2 4 5 4 5 -2 2 E=round(10*rand(2,4))-5 E = -4 4 -2 -2 -5 -3 2 0 [B,C;E] ??? Error using ==> vertcat All rows in the bracketed expression must have the same number of columns. eps_2=zeros(4,1);eps_2(2,1)=1 eps_2 = 0 1 0 0 I4=eye(4) I4 = 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 for k=1:4, eval(['e',num2str(k),'=I4(:,',num2str(k),')']) end ??? for k=1:4, eval(['e',num2str(k),'=I4(:,',num2str(k),')']) end | Error: Missing operator, comma, or semicolon. for k=1:4, eval(['e',num2str(k),'=I4(:,',num2str(k),')']), end e1 = 1 0 0 0 e2 = 0 1 0 0 e3 = 0 0 1 0 e4 = 0 0 0 1 [e1,e2,e3,e4] ans = 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 [e1';e2';e3';e4'] ans = 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 A A = -3 -3 4 3 -2 2 2 1 1 -2 -2 -1 0 3 -2 0 4 4 2 0 diag(A) ans = -3 2 0 2 diag(ans) ans = -3 0 0 0 0 2 0 0 0 0 0 0 0 0 0 2 D=diag(A) D = -3 2 0 2 diag(D) ans = -3 0 0 0 0 2 0 0 0 0 0 0 0 0 0 2 diag(D,1) ans = 0 -3 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 diag(D,-11) ans = Columns 1 through 13 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -3 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 Columns 14 through 15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 diag(D,-1) ans = 0 0 0 0 0 -3 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 2 0 diag(diag(A)) ans = -3 0 0 0 0 2 0 0 0 0 0 0 0 0 0 2 A A = -3 -3 4 3 -2 2 2 1 1 -2 -2 -1 0 3 -2 0 4 4 2 0 triu(A) ans = -3 -3 4 3 -2 0 2 1 1 -2 0 0 0 3 -2 0 0 0 2 0 tril(A) ans = -3 0 0 0 0 2 2 0 0 0 -2 -1 0 0 0 0 4 4 2 0 A(:) ans = -3 2 -2 0 -3 2 -1 4 4 1 0 4 3 1 3 2 -2 -2 -2 0 A(2) ans = 2 A.' ans = -3 2 -2 0 -3 2 -1 4 4 1 0 4 3 1 3 2 -2 -2 -2 0 X=[1+i,1,2+i;i,i,2*i] X = 1.0000 + 1.0000i 1.0000 2.0000 + 1.0000i 0 + 1.0000i 0 + 1.0000i 0 + 2.0000i X' ans = 1.0000 - 1.0000i 0 - 1.0000i 1.0000 0 - 1.0000i 2.0000 - 1.0000i 0 - 2.0000i X X = 1.0000 + 1.0000i 1.0000 2.0000 + 1.0000i 0 + 1.0000i 0 + 1.0000i 0 + 2.0000i X'' ans = 1.0000 + 1.0000i 1.0000 2.0000 + 1.0000i 0 + 1.0000i 0 + 1.0000i 0 + 2.0000i A=[1,2,3;0,1.0] ??? Error using ==> vertcat All rows in the bracketed expression must have the same number of columns. A=[1,2,3;0,1,0] A = 1 2 3 0 1 0 B=[1,0;2,0;0,1] B = 1 0 2 0 0 1 A*B ans = 5 3 2 0 diary off