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Re: Non-deterministic numerical inaccuracies in Mathematica 7

  • To: mathgroup at smc.vnet.net
  • Subject: [mg95698] Re: Non-deterministic numerical inaccuracies in Mathematica 7
  • From: David Bailey <dave at removedbailey.co.uk>
  • Date: Sun, 25 Jan 2009 06:51:15 -0500 (EST)
  • References: <gjcuio$cnf$1@smc.vnet.net> <gjkvd4$92g$1@smc.vnet.net> <gjv743$ovs$1@smc.vnet.net>

Daniel Lichtblau wrote:
>>
>> The bad news is that it is a consequence of the M.K.L. which can't
>> be avoided. The good news is that you should not care about it.
>> If the difference seems important then you are doing something
>> wrong.
>>

I think we should care about it! Lots of programs have different 
behaviours depending on a real number threshold, and this behaviour 
means that there is the possibility of a test flipping different ways on 
different runs of a program!

This could be a debugging nightmare, and will be in the back of people's 
minds whenever anything 'strange' happens.

Would it not be possible to revert to the previous, slightly less 
optimal, library until (presumably) the library is fixed?

David Bailey
http://www.dbaileyconsultancy.co.uk


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