st: re: generating determinant of Hessian matrix over observations

[Kit Baum <baum@bc.edu>]

The hard way:

modify Asgar's code presented to replace one observation at a time in  
det_H.

The easy way: the det of a 2x2 matrix does not require matrix  
calculations; just calculate the det as A*C - B*B.

* corrected code

gen det_H = .
qui forvalues i = 1/43 {
    matrix H = (A[`i'], B[`i'] \ B[`i'], C[`i'])
    replace det_H =  det(H) in `i'
}

* a much simpler solution

gen easydetH = A*C - B^2

l det_H easydetH


Kit Baum, Boston College Economics and DIW Berlin
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html


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