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Re: WHERE problems (longish) [message #35912 is a reply to message #35911]

Tue, 22 July 2003 08:47

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Benjamin Panter writes:

> The values which have -1 certainly exist - and were generated in exactly
> the same way as the others. I've put the array online if anyone fancies
> looking at it - http://www.roe.ac.uk/~bdp/where_problem.idl
>
> Am I being stupid again? What is special about 2980,3000 and 3020??

There is nothing special about *those* numbers, but those
are not the numbers you are using in your WHERE statement.
You are using 2980.0, 3000.0, and 3020.0. While there isn't
a big difference between integers and floats to you, there
is a HUGE difference to a computer. Better read these articles:

http://www.dfanning.com/math_tips/sky_is_falling.html
http://www.dfanning.com/math_tips/razoredge.html

Cheers,

David

--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		Re: WHERE problems (longish) By: Paul Van Delst[1] on Tue, 22 July 2003 09:45
		Re: WHERE problems (longish) By: David Fanning on Tue, 22 July 2003 09:07
		Re: WHERE problems (longish) By: Benjamin Panter on Tue, 22 July 2003 08:59
		Re: WHERE problems (longish) By: Justin[2] on Tue, 22 July 2003 08:49
		Re: WHERE problems (longish) By: David Fanning on Tue, 22 July 2003 08:47

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