**procedure**:

```
Data preparation: X X∗
    Compute dot product matrix: X∗ 0
                                    X∗ ð Þ n � 1 M
    Eigenanalysis: AL2
                     A0 X∗ 0
                              X∗
    Compute eigenvectors: U X∗ AL
    Keep first 7 components: U7 ½ � u1⋯u7
    Compute 7 features: Y Ud
                               0
                               X
end procedure.
```