similarity of map points

[Navid Rekabsaz]

Thanks for informative and concise tutorial,

I am wondering if the definition of the similarity of the map points should be based on Y points and not X points.

it is
(q_{ij} = \frac{f(\left| x_i - x_j\right|)}{\displaystyle\sum_{k \neq i} f(\left| x_i - x_k\right|)}

and should be

(q_{ij} = \frac{f(\left| y_i - y_j\right|)}{\displaystyle\sum_{k \neq i} f(\left| y_i - y_k\right|)}

Is it correct?