m232d2 whos Name Size Bytes Class A 3x3 72 double array Ai 3x3 72 double array Aiex 3x3 72 double array Asin 4x4 128 double array Asw 5x5 200 double array B 3x6 144 double array B1 3x6 144 double array B2 3x6 144 double array B3 3x6 144 double array E 3x3 72 double array E2 3x3 72 double array L 3x3 72 double array U 3x3 72 double array ans 3x3 72 double array button 1x3 6 char array Grand total is 188 elements using 1486 bytes A=Asw A = 2 1 1 1 1 -4 -1 -1 -1 -1 2 2 2 0 2 6 5 2 2 4 2 3 9 11 6 m=[2 -1 -3 -1]; P=eye(5); L=eye(5); E1=eye(5); E1(2:5,1)=m' E1 = 1 0 0 0 0 2 1 0 0 0 -1 0 1 0 0 -3 0 0 1 0 -1 0 0 0 1 L(2:5,1)=-m' L = 1 0 0 0 0 -2 1 0 0 0 1 0 1 0 0 3 0 0 1 0 1 0 0 0 1 A1=E1*A A1 = 2 1 1 1 1 0 1 1 1 1 0 1 1 -1 1 0 2 -1 -1 1 0 2 8 10 5 m=[-1 -2 -2]; E2=eye(5); E2(3:5,2)=m' E2 = 1 0 0 0 0 0 1 0 0 0 0 -1 1 0 0 0 -2 0 1 0 0 -2 0 0 1 L(3:5,2)=-m' L = 1 0 0 0 0 -2 1 0 0 0 1 1 1 0 0 3 2 0 1 0 1 2 0 0 1 A2=E2*A1 A2 = 2 1 1 1 1 0 1 1 1 1 0 0 0 -2 0 0 0 -3 -3 -1 0 0 6 8 3 P([3,4],:)=P([4,3],:) P = 1 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 1 A2=P*A2 A2 = 2 1 1 1 1 0 1 1 1 1 0 0 -3 -3 -1 0 0 0 -2 0 0 0 6 8 3 L L = 1 0 0 0 0 -2 1 0 0 0 1 1 1 0 0 3 2 0 1 0 1 2 0 0 1 L([3,4],1:2)=L([4,3],1:2) L = 1 0 0 0 0 -2 1 0 0 0 3 2 1 0 0 1 1 0 1 0 1 2 0 0 1 A2 A2 = 2 1 1 1 1 0 1 1 1 1 0 0 -3 -3 -1 0 0 0 -2 0 0 0 6 8 3 E3=elemat(5,5,3,2) E3 = 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 2 0 1 L(5,3)=-2 L = 1 0 0 0 0 -2 1 0 0 0 3 2 1 0 0 1 1 0 1 0 1 2 -2 0 1 A3=E3*A2 A3 = 2 1 1 1 1 0 1 1 1 1 0 0 -3 -3 -1 0 0 0 -2 0 0 0 0 2 1 E4=elemat(5,5,4,1) E4 = 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1 1 L(5,4)=-1; U=E4*A3 U = 2 1 1 1 1 0 1 1 1 1 0 0 -3 -3 -1 0 0 0 -2 0 0 0 0 0 1 L*U ans = 2 1 1 1 1 -4 -1 -1 -1 -1 6 5 2 2 4 2 2 2 0 2 2 3 9 11 6 A A = 2 1 1 1 1 -4 -1 -1 -1 -1 2 2 2 0 2 6 5 2 2 4 2 3 9 11 6 A-L*U ans = 0 0 0 0 0 0 0 0 0 0 -4 -3 0 -2 -2 4 3 0 2 2 0 0 0 0 0 P*A ans = 2 1 1 1 1 -4 -1 -1 -1 -1 6 5 2 2 4 2 2 2 0 2 2 3 9 11 6 P*A-L*U ans = 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 A=Asin A = 1 1 1 0 1 1 2 1 1 1 2 2 1 1 3 0 L=eye(4); E1=eye(4); m=[-1 -1 -1]; E1(2:4,1)=m'; L(2:4,1)=-m'; A1=E1*A A1 = 1 1 1 0 0 0 1 1 0 0 1 2 0 0 2 0 m=[-1 -2]; E2(3:4,3)=m'; L(3:4,3)=-m'; A2=E2*A1 ??? Error using ==> * Inner matrix dimensions must agree. E2=eye(4); E2(3:4,3)=m'; A2=E2*A1 A2 = 1 1 1 0 0 0 1 1 0 0 -1 -2 0 0 0 -4 E2 E2 = 1 0 0 0 0 1 0 0 0 0 -1 0 0 0 -2 1 E2=eye(4);E2(3:4,2)=m'; E2 E2 = 1 0 0 0 0 1 0 0 0 -1 1 0 0 -2 0 1 A2=E2*A1 A2 = 1 1 1 0 0 0 1 1 0 0 0 1 0 0 0 -2 L L = 1 0 0 0 1 1 0 0 1 0 1 0 1 0 2 1 L(3,2)=1; L(4,2:3)=[2 0] L = 1 0 0 0 1 1 0 0 1 1 1 0 1 2 0 1 A2 A2 = 1 1 1 0 0 0 1 1 0 0 0 1 0 0 0 -2 E3=elemat(4,4,3,2); L(4,3)=-2 L = 1 0 0 0 1 1 0 0 1 1 1 0 1 2 -2 1 U=E3*A2 U = 1 1 1 0 0 0 1 1 0 0 0 1 0 0 0 0 L L = 1 0 0 0 1 1 0 0 1 1 1 0 1 2 -2 1 L* ??? L* | Missing operator, comma, or semi-colon. L*U ans = 1 1 1 0 1 1 2 1 1 1 2 2 1 1 3 0 A A = 1 1 1 0 1 1 2 1 1 1 2 2 1 1 3 0 U U = 1 1 1 0 0 0 1 1 0 0 0 1 0 0 0 0 diary off