% Matlab diary from cs110a class #4, Jan 10 2005.
%
% This is what I typed in class.  
%
% Type it into Matlab yourself to
% reproduce the output I showed.

1 + eps
ans - 1
e  = 2/3 * eps
1 + e
ans - 1
e  = 1/3 * eps
1 + e
ans-1
clc
A = [1 2 3 ; 4 5 6 ; 7 8 9]
P = [1 0 0 ; 0 0 1 ; 0 1 0]
P * A
A * P
A(1,3)
A
A( [2 3] , [1 3] )
A( [2 3] , : )
A(:,:)
A
P*A
A ( [1 3 2] , :)
p = [1 3 2]
p
P
A = rand(7)
format short
A
A = hilb(7)
A = 1 ./ hilb(7)
I = eye(7)
help randperm
p = randperm(7)
A
A(p,:)
P = I(p,:)
P*A
A(p,:)
clc
b = rand(4,1)
A = rand(4)
x = A \ b
A*x - b
[L, U, P] = lu(A)
P*A  -   L*U