[Gretl-devel] exp domain error even though missings are "deactivated"

Hi, I'm trying to work with matrices converted from series/lists that contain missings, in order to vectorize and hopefully speed up code. I'm working around the fact that misszero() doesn't work for matrices by using the ternary operator to only apply formulas selectively to the non-missings. (I vaguely remember a discussion about matrices and misszero(), but don't recall the details anymore. Probably I should go and dig it up in the archives.) One thing I'm puzzled about is that I get "domain error" warnings about the exp() function, even though I only apply it to the non-missings. Example: <hansl> a = exp(NA) # memo: no "domain error" for the scalar case matrix m = I(4) matrix m2 = !m ? NA : m # create some "nan" in a matrix print m2 # look at the nan, they're there! matrix check = exp(m2) # "domain error" ok, expected matrix m3 = isnan(m2) ? 0 : exp(m2) # but why here? </hansl> After the last line m3 doesn't contain missings/nan, and so the code works, but then why the warning message? I could imagine that both branches of the ternary operation are executed and then afterwards the needed results are collected and combined, but that would seem quite inefficient computationally, no? thanks, sven