st: macro `if' in nonlinear least squares

[Francesca Colantuoni <f.colantuoni9@gmail.com>]

I am programming a nonlinear least square regression, and I am trying
to find the best way to do it based on variuos examples that I found
online.

In the following code, I have trouble understanding what stata does
with the macro `if' at the end of the generate command. Would anybody
clarify that for me? I could not find an explanation for this use of
"if" in either [P] or [U] manual (or Google).

// Some temporary variables
    tempvar kterm lterm
    generate double `kterm' = `delta'*`capital'^(-1*`rho') `if'
    generate double `lterm' = (1-`delta')*`labor'^(-1*`rho') `if'

    // Now fill in dependent variable
    replace `logout' = `b0' - 1/`rho'*ln(`kterm'+`lterm') `if'

Best Regards,
Francesca
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