matlab svd tests

gistfile1.txt

clf
hold on;
grid on;

# item labels
I = { 
	'Dr Who', 
	'Eastenders', 
	'Farmer Seeks Wife', 
	'Eurovision', 
	'Newsnight', 
	'Coronation Street', 
	'Top of the Pops', 
 	'Big Brother' 
    }

L =  { 'Acracia', 'Libby', 'Michele', 'MS-', 'Nevali','VickyB','Yod', 'Yvesr', 'Laroyo' } # who
# edit as an Items x People matrix (easier to add people)
A = [ 4 1 0 3 4 1 3 4 ; # Acracia
      5 2 1 5 5 2 4 1 ; # Libby
      4 1 1 4 3 1 3 3 ; # Michele
      4 5 2 5 5 4 4 0 ; # MS-
      5 2 1 3 3 1 2 0 ; # Nevali
      5 2 0 3 3 2 2 4 ; # VickyB
      1 0 1 1 1 0 1 0 ; # Yod
      3 4 1 4 4 5 3 4 ; # YvesR
      5 2 1 4 4 3 3 5 ; # Laroyo
]

A = A' # transpose -> people across the top ...

[U,S,V] = svd(A)

# series first
a = U
X =  a(: , 1:1)
Y =  a(: , 2:2)
echo on
for K = 1:size(I,1)
  text(X(K),Y(K), I(K), 'FontWeight', 'bold' ) 
end
echo off

# users
a = V
P =  a(: , 1:1)
Q = a(: , 2:2)
for K = 1:size(L,2)
  text(P(K),Q(K),  L(K), 'FontWeight', 'light' )
end

print("notubery2a.png","-dpng")

# Let's add an unseen user, embed him in the 2D space derrived from the others' ratings
# balthasar = [4 1 1 4 3 1 3 3] # like Michele
balthasar = [ 4 5 2 5 5 2 4 1 ] # like MS- and Libby, 50/50
# balthasar = [ 0 0 2 5 5 0 4 0 ] # like MS- and Libby, 50/50 with 4 missing

u2 = U(:,1:2)
eig2inv = inv ( S(:,1:2)(1:2,:) )
embed = balthasar * u2 * eig2inv
text(embed(1), embed(2), "Balthasar")


print("notubery2b.png","-dpng")