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MathGroup Archive 2004

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Re: Re: Arbitrary-precision numbers in patterns

  • To: mathgroup at smc.vnet.net
  • Subject: [mg45417] Re: [mg45409] Re: Arbitrary-precision numbers in patterns
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Wed, 7 Jan 2004 01:09:07 -0500 (EST)
  • References: <btb906$jqd$1@smc.vnet.net> <200401060917.EAA00315@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Nobody has ever tried to do anything of the sort. This example is  
(probably)  just a bug. Some of the other things Maxim has written 
about were also just bugs others more qustionably so. But Maxim has 
made it very clear (and if I am misrepresenting him I hope he will 
correct me) that he does not really much care about mere bugs, for as 
he writes:

"But in general, my opinion is that it is only to be expected ...".

He in fact even stressed that some things others have called bugs were 
not bugs in his opinion.  What he objects to is not even the 
incompleteness of the Mathematica documentation (all of us would like 
more and better documentation) but rather the fundamental design of 
Mathematica. The only way to satisfy him, and those who think like him, 
is to re-write the whole thing from scratch on the basis of a very 
differnt philosophy. However, that is very unlikely to happen, because, 
for one, there are quite many people who are, on the whole, rather 
happy with the present design. It would therefore be much more sensible 
for those who are not to find themselves some activity more 
"predictable" than Mathematica programming.
  (I have a few suggestions but the moderator might not allow them here 
;-)

Andrzej Kozlowski
Chiba, Japan
http://www.mimuw.edu.pl/~akoz/




On 6 Jan 2004, at 18:17, Bobby R. Treat wrote:

> I can't WAIT to hear somebody explain why this is acceptable 
> behavior!!!
>
> Bobby
>
> Maxim <dontsendhere@.> wrote in message 
> news:<btb906$jqd$1 at smc.vnet.net>...
>> Compare
>>
>> In[1]:=
>> Do[ f[k] = k, {k, 1., 17.} ]
>> f[1.`20]
>> Clear[f]
>>
>> Out[2]=
>> 1.
>>
>> and
>>
>> In[1]:=
>> Do[ f[k] = k, {k, 1., 18.} ]
>> f[1.`20]
>> Clear[f]
>>
>> Out[2]=
>> f[1.0000000000000000000]
>>
>> -- and the user's best bet to figure out how it'll work is probably to
>> flip a coin.
>>
>> The reason is probably just that the hashing mechanism breaks down,
>> because the result returned by Mathematica changes after it re-sorts
>> some internal table of DownValues for f (the 'boundary value' 17 is 
>> for
>> version 5.0 on my machine; if 17. and 18. don't work, try 2. and 
>> 100.).
>> But in general, my opinion is that it is only to be expected -- when 
>> we
>> don't even know for sure how the definitions for f can be reordered.
>>
>> Maxim Rytin
>> m.r at prontomail.com
>
>
>


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