Allin,
thanks a lot, that was the issue. When I thus try to constrain the calculation not to go
in the direction where negative lambdas are created by
<hansl>
function scalar getNegativesCount(series * xSeries)
scalar xRetVal = 0
loop xIdx = 1..$nobs
if missing( xSeries[xIdx] ) = 0
if xSeries[xIdx] < 0.0
xRetVal = xRetVal + 1
endif
endif
endloop
return xRetVal
end function
...# ESTIMATIONmle ll = xCheck == 0 ? -ln(lambda) - sqrtPark/lambda : NA series
lambda = mean(sqrtPark) series lambda = c_ + rng * sqrtPark(-1) + rng2 *
sqrtPark(-2) + err_ * lambda(-1) + err_2 * lambda(-2) scalar xCheck =
getNegativesCount(& lambda) params c_ rng rng2 err_ err_2end mle
--robust#ESTIMATION</hansl>I get a "Scalar loglikelihood: can't do
QML". So, how do I tell the optimizer that in case it runs to negative lambda, it
should "go away" from that parameter combination? I also tried to replace
the <hansl>...mle ll = xCheck == 0 ? -ln(lambda) - sqrtPark/lambda :
NA...</hansl>with <hansl>...mle ll = xCheck == 0 ? -ln(lambda) -
sqrtPark/lambda : -100000...</hansl>but it produced the same error.Many
thanks, Daniel