On Wed, 30 Jan 2013, Henrique Andrade wrote:

(...)
> Now it is not working anymore :-( Using the "test case" I provided
> everything works:
>
> <hansl>
> open data9-7
> loop i = 1..2
>    arima $i 1 2 ; QNC
>    matrix r = $["roots"] # overwrites "r"
>    print r
> endloop
> </hansl>
>

> But with my "real world" example it doesn't [...]

> loop for P=0..max_ar_lags --quiet
>    loop for Q=0..max_ma_lags --quiet
>        matrix especificacoes = especificacoes | {$P, 1, $Q}
>    endloop
> endloop

The trouble is that the first model estimated in your "real
world" example doesn't have any ARMA roots (P = Q = 0). For
all the other specifications you'll get the $["roots"] matrix
OK.