[Radiance-general] total -p and zeroes

[Greg Ward]

Hi Axel,

This is really a bug.  Total computes products by converting to a log  
domain, which of course doesn't work for zero.  I can fix this  
problem, and will do so in the next release.

Cheers for pointing it out.
-Greg

P.S.  The reason for converting to log is that it allows geometric  
means to be computed for almost any set of numbers, which would  
overflow a straight product.

> From: Axel Jacobs <jacobs.axel at gmail.com>
> Date: January 29, 2010 8:51:49 AM PST
>
> Dear list,
>
> I'm trying to use total -p to multiply two rows of data like this:
>
> $ echo -e "0 1 2 3\n2 3 4 5"
> 0 1 2 3
> 2 3 4 5
>
> $ echo -e "0 1 2 3\n2 3 4 5" |total -p
> 2	3	8	15
>
> I would expect 0 * 2 = 0 in the first column. Does the -p option not  
> like zeroes? A straight-forward sum gives the expected result:
>
> $ echo -e "0 1 2 3\n2 3 4 5" |total
> 2	4	6	8
>
> Regards
>
> Axel