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Re: divide by zero problems [message #15392 is a reply to message #15362]

Sat, 15 May 1999 00:00

korpela
Messages: 59
Registered: September 1993

Member

In article <bowman-1405991756240001@tl6-218-141.tca.net>,
Kenneth P. Bowman <bowman@null.tamu.edu> wrote:
>> IDL> PRINT, !VALUES.F_NAN EQ !VALUES.F_NAN
>> 1
>> % Program caused arithmetic error: Floating illegal operand
>
> I thought that by definition NaNs are not a number and hence not equal to
> *anything* else. Thus the FINITE function.

That's the point. In IEEE math there is no need for a FINITE function.
X eq X is enough to test for NaN. X EQ !Values.F_NAN should always return
0. Even if X is NaN. Period. Excamation point!

If RSI thinks it's not important that IDL be IEEE compliant, they're wrong.
I may consider that bit of non-portability/non-compliance a good reason not
to code for IDL under ANY platform.

Eric

--
Eric Korpela | An object at rest can never be
korpela@ssl.berkeley.edu | stopped.
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[Message index]

		divide by zero problems By: Mark Rehbein on Tue, 11 May 1999 00:00
		Re: divide by zero problems By: korpela on Sat, 15 May 1999 00:00
		Re: divide by zero problems By: bowman on Fri, 14 May 1999 00:00
		Re: divide by zero problems By: mallors on Fri, 14 May 1999 00:00
		Re: divide by zero problems By: Mark Hadfield on Fri, 14 May 1999 00:00
		Re: divide by zero problems By: davidf on Thu, 13 May 1999 00:00
		Re: divide by zero problems By: korpela on Thu, 13 May 1999 00:00
		Re: divide by zero problems By: Frank Monaldo on Tue, 18 May 1999 00:00

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