Math errors in python

Bengt Richter bokr at oz.net
Mon Sep 20 03:41:06 CEST 2004


On 20 Sep 2004 00:35:33 GMT, bokr at oz.net (Bengt Richter) wrote:
[...]
> 
>If you add a small Decimal delta repeatedly, will it get rounded away like the floating point
>version, or will accuracy get promoted, or what? Sorry, I haven't read the docs yet ;-/
>
I needn't have used 1e-300 to get the effect -- 1e-16 is relatively small enough:

 >>> acc = 1.0
 >>> for i in xrange(100): acc += 1e-16
 ...
 >>> acc
 1.0
 >>> ED(acc, 'all')
 ED('1')
 >>> ecc = ED(1)
 >>> for i in xrange(100): ecc += ED('1e-16')
 ...
 >>> ecc
 ED('1.00000000000001')

Regards,
Bengt Richter



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