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Re: where() and IEEE NaN

korpela@islay.ssl.berkeley.edu (Eric J. Korpela) writes:

>In article <7vvkuf$hk4@post.gsfc.nasa.gov>,
>William Thompson <thompson@orpheus.nascom.nasa.gov> wrote:
>>Isn't it simpler (and faster) to say
>>	IDL> print,where(a ne a)

>It is on IEEE compliant platforms.  But IDL on some platforms
>is not IEEE compliant.  My solution is not to use those platforms.
>If forced to use one of those platforms by my employer, my solution would
>be not to use IDL.  Anyone at RSI listening?  

I thought the only platform that wasn't IEEE compliant was OpenVMS, where the
VAX floating point notation doesn't included NaN values.  However, didn't RSI
recently change the OpenVMS version to use IEEE floating point numbers instead,
so that it's now IEEE compliant too.  Of course, it may be that I'm missing
something more subtle, or there's some non-IEEE platform out there I'm not
familiar with.

Actually, the comment that the above command is confusing to people who don't
know what's going on is valid.  Vincenzo's suggestion of using FINITE(/NaN) is
probably better, and should be (at least) just as fast.


William Thompson