F_ML= log|S| − log|Σ| + tr(SΣ − 1) − k

Where:

- log = natural logarithm function (base e)

- || = matrix determinant

- k = variable number in the correlation (or covariance) matrix

- tr = trace matrix algebra function summing diagonal elements

- S = observed matrix

- Σ = reproduced matrix

- Σ − 1 = inverse of reproduced matrix Σ