[ic] Screwey Math
Andrew Shelansky
andrew at lunsfordgroup.com
Fri Nov 12 14:55:42 EST 2004
On Thu, 11 Nov 2004, Russell Mann wrote:
> Any idea why IC thinks
>
> 86.85 - 86.85 = 1.4210854715202e-14
>
> And
>
> 46.9 - 46.9 = 7.105427357601e-15
>
> This is a new feature, not sure why it started. My code is for determining
> when to tell someone they have a discount:
We encountered the same problem when trying to determine if a collection
of discounts made the order free (and to prevent better-than-free
deals).
Ultimately we decided to check to see whether we were less than $0.005.
We figured any irder total lower than that would be free.
A similar idea should work for you unless you are selling products that
cost less than that -- although look at your numbers, you could use
$0.00005 and be just fine, probably.
-- Andrew
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