Starting diary file diary-11-Oct-2010.txt

A = rand(5);
[L, U, p] = lutx(A)
A
A(p,:)
    
[LL,UU,PP] = lu(A);
LL
L
p
PP

A
A(p,:)
PP*A

PP
p

A = testmat(5)
A(p,:)
PP*A

A(:,p)
A * PP
A * PP'

PP
PP'

PP * A * PP'
A(p,p)

PP * PP'
PP' * PP
inv(PP)
PP'

A
PP * A
PP' * (PP*A)

p
B = A(p,:)
B(p,:)
PP*PP*A

PP
p
PP'
pinv = [2;4;3;1;5]

B = A(p,:)
C = B(pinv,:)
p
pinv

A = rand(5)
A * A'
inv(A)

eye(6)
v = [ 3 1 4 1 5 9]
diag(v)

A
diag(A)
diag(diag(A))
A - diag(diag(A))

v = [ 3 1 4 1 5 9]
D = diag(v)
A = testmat(6)
D * A
A * D

A(:,1)
sum(A(:,1))
sum(A)
sum(A')
csum = sum(A)

1 / csum
1 ./ csum

B = testmat(2)
B*B
B .* B

1 ./ csum
D = diag(1./csum)
A * D
sum(ans)

load LU
A
[L,U,P] = lu(A)
L * U

diary off