V = zeros(1,5)
V =
     0     0     0     0     0

    W = 2*ones(5)+3*eye(5)
W =
     5     2     2     2     2
     2     5     2     2     2
     2     2     5     2     2
     2     2     2     5     2
     2     2     2     2     5

    W = hilb(5)*(eye(5)+invhilb(5))
W =
    2.0000    0.5000    0.3333    0.2500    0.2000
    0.5000    1.3333    0.2500    0.2000    0.1667
    0.3333    0.2500    1.2000    0.1667    0.1429
    0.2500    0.2000    0.1667    1.1429    0.1250
    0.2000    0.1667    0.1429    0.1250    1.1111

    X = hilb(5)^5-2*ones(5)
X =
    3.5717    1.2346    0.3333   -0.1612   -0.4776
    1.2346   -0.1220   -0.6453   -0.9323   -1.1161
    0.3333   -0.6453   -1.0227   -1.2298   -1.3623
   -0.1612   -0.9323   -1.2298   -1.3930   -1.4974
   -0.4776   -1.1161   -1.3623   -1.4974   -1.5839

    diag(X)
ans =
    3.5717
   -0.1220
   -1.0227
   -1.3930
   -1.5839

    Y = diag(diag(X))
Y =
    3.5717         0         0         0         0
         0   -0.1220         0         0         0
         0         0   -1.0227         0         0
         0         0         0   -1.3930         0
         0         0         0         0   -1.5839