summation problem

["Manish" <mrmanish(at)bigfoot.com>]

Hi, I'm pretty new to IDL (well, actually completely new!) and was wondering
if anyone could help with a small problem.

I have a program which produces an array of values of sunlight flux during
the day.  Unfortunately, it produces crazy numbers before the sunrises and
after it sets(as expected).  I'm summing the values throughout the day to
get a total integrated day flux, but here's the problem - is there a way of
telling the TOTAL function to ignore negative numbers and NaN numbers?

I guess this is a simple problem, but would appreciate any help

Many thanks,

Manish