EViews.com

Dear Fellows
im using eviews 10 student version

i want get log on non positive number

i have used this formula
lfdi=log(fdi(-1))


1980 na
1981 -0.082
1982 1.222
1983 na
1984 na
..... -0.225
.. -0.025
.. 2.225
. 3.265

2017 2.2563

How to deal with this situation ''NA'' and some log are still non positive

please advise
thank in advance

Logs can be negative, but the logs of a non-positive number don't exist.