Re: Natural keys vs Aritficial Keys
From: paul c <toledobythesea_at_oohay.ac>
Date: Sat, 23 May 2009 03:28:08 GMT
Message-ID: <c3KRl.29093$PH1.5524_at_edtnps82>
>
> If expressing exact rationals is what you want, then that is trivially
> done using integer arithmetic - as is fixed point decimal. Hardware
> decimals, which essentially died with the VAX, don't help you express
> rationals.
>
> Have a play with these:
> http://gmplib.org/ (see mpq for rationals)
> http://docs.sympy.org/
....
Date: Sat, 23 May 2009 03:28:08 GMT
Message-ID: <c3KRl.29093$PH1.5524_at_edtnps82>
toby wrote:
> On May 22, 9:10 pm, paul c <toledobythe..._at_oohay.ac> wrote:
>> Bob Badour wrote: >>> paul c wrote: >>>> Bob Badour wrote: >>>>> paul c wrote: >> ... >>>>>> Oh, just remembered another one - fixed-point decimal arithmetic! >>>>> What do you need that for? >>>> To get the same answer as the lawyer with his amortization tables. >>> Integers are integers no matter the base. >> Sure they are, but I was talking about decimal points. Eg., it bugs me >> that the most widely-used (that doesn't mean most popular) cpu >> 'architecture', Intel's, can't express the fraction 2/5 exactly.
>
> If expressing exact rationals is what you want, then that is trivially
> done using integer arithmetic - as is fixed point decimal. Hardware
> decimals, which essentially died with the VAX, don't help you express
> rationals.
>
> Have a play with these:
> http://gmplib.org/ (see mpq for rationals)
> http://docs.sympy.org/
....
The point has nothing to do with rationals, some decimal fractions are irrational. I never said a cpu should express exact values, rather it should express the exact same values people who are accustomed to decimal arithmetic or traditional slide-rules come up wiith. To talk otherwise is to argue for Betamax. Received on Sat May 23 2009 - 05:28:08 CEST