1.#QNAN Solution

[Greg Corradini]

Hello all,
I'm running descriptive stats on mileages from a database (float numbers,
about a million records). My sum returns 1.#QNAN, which I understand from
searching this forum is an error.

While I'm looking for help in solving this problem, I'm more interested in a
general explanation about the cause of this problem. Any ideas?

Thanks
Greg Corradini

 

[Grant Edwards]

I'm running descriptive stats on mileages from a database
(float numbers, about a million records). My sum returns
1.#QNAN, which I understand from searching this forum is an
error.

Not necessarily. You've ended up with a floating point "not a
number" value (AKA a NaN). That might or might not be an
error. Whether it's an error not not depends on your input
data and your algorithm.

While I'm looking for help in solving this problem, I'm more
interested in a general explanation about the cause of this
problem.

If you're asking how you end up with a NaN, there are several
ways to generate a NaN:

0/0

Inf*0

Inf/Inf

Inf-Inf

Almost any operation on a NaN

http://en.wikipedia.org/wiki/NaN
http://steve.hollasch.net/cgindex/coding/ieeefloat.html

 

[Greg Corradini]

Thanks for you help Grant

Not necessarily. You've ended up with a floating point "not a
number" value (AKA a NaN). That might or might not be an
error. Whether it's an error not not depends on your input
data and your algorithm.


If you're asking how you end up with a NaN, there are several
ways to generate a NaN:

0/0

Inf*0

Inf/Inf

Inf-Inf

Almost any operation on a NaN

http://en.wikipedia.org/wiki/NaN
http://steve.hollasch.net/cgindex/coding/ieeefloat.html

 

[Dennis Lee Bieber]

Hello all,
I'm running descriptive stats on mileages from a database (float numbers,
about a million records). My sum returns 1.#QNAN, which I understand from
searching this forum is an error.

Are you sure none of the summed values contained a database NULL
value?

Or that you can't create some query to do the summing for you <G>
--
Wulfraed Dennis Lee Bieber KD6MOG
(e-mail address removed) (e-mail address removed)
HTTP://wlfraed.home.netcom.com/
(Bestiaria Support Staff: (e-mail address removed))
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