Scaling by Majorizing a Complicated Function, the iterative algorithm to find an optimal Configuration.

1. Initialize

   1.a. Get initial Configuration Z

   1.b. Set stress σ_n^[0] to a very large value.

   1.c. Set iteration counter k = 0

2. Increase iteration counter by one: k = k + 1

3. Calculate distances d_ij(Z).

4. Transform dissimilarities δ_ij into disparities d′_ij.

5. Standardize the disparities so that η_d′² = n(n–1)/2.

6. Compute the Guttman transform X^[k] of Z.

7. Compute new distances d_ij(X^[k]).

8. Compute normalized stress σ_n (d′, X^[k])

9. If |σ_n^[k] – σ_n^[k–1]| / σ_n^[k–1] < ε or k > maximumNumberOfIterations, then stop

10. Set Z = X^[k], and go to 2.

This algorithm goes back to De Leeuw (1977).