Re: [BLACKBOX] Math.Pi (was: CONSTant expressions)

From: [at]} <CFB>
Date: Mon, 21 Jan 2008 10:10:50 +1030

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>From: BlackBox [mailto:BLACKBOX{([at]})nowhere.xy
>Sent: Sunday, 20 January 2008 11:16 PM
>To: BLACKBOX{([at]})nowhere.xy
>Subject: Re: [BLACKBOX] CONSTant expressions
>
>> CFB Software wrote:
>> OutBool ('pi = Pi ? ', pi = Math.Pi ()); (* FALSE *)
>>
>> I would have expected the third result to be TRUE - have I
>> fallen into a carefully-laid trap?
>
> The call Math.Pi () leaves an 80-bit result in the floating point
>register, that
>is then compared with a 64-bit rounded version. Result? they
>are different!

I'm not convinced that the behaviour is intentional. Math.Pi is documented
as *returning* a REAL. i.e. 64 bits.

Additionally, how does your theory explain this one?

     OutBool ('Pi = Pi ? ', Math.Pi() = Math.Pi() ); (* FALSE *)

Regards,
Chris

Chris Burrows
CFB Software
http://www.cfbsoftware.com/cp

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Received on Mon Jan 21 2008 - 00:40:50 UTC