[Tutor] Need help with rewriting script to use Decimal module

[Terry Carroll]

On Mon, 1 Jan 2007, Dick Moores wrote:

> bestFracForMinimumError() is only a small part of a program I wrote 
> long ago, called frac.py 

Dick, if your goal is to have a routine to get the fraction with the least 
possible error (as opposed to learing how to use Decimal), have a look at 
this recipe from the Python Cookbook:

 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52317

> dec = .345765988765560057657654654
> me = .0000000001
> num, denom, error = bestFracForMinimumError(dec, me)
> print "%f = %d/%d with %f per cent error" % (dec, num, denom, error)

The parameters are different from yours, but as I understand it, your 
equivalent is:

>>> dec = .345765988765560057657654654
>>> me = .0000000001
>>> max_denom = 1/me
>>> (num, denom) = farey(dec,max_denom)
>>> error = abs((num/denom) - dec) *100
>>> print "%f = %d/%d with %f per cent error" % (dec, num, denom, error)
0.345766 = 40258524/116432863 with 0.000000 per cent error
>>>