Hi,

I am looking for an easy way to do significant figure calculations in

python (which I want to use with a class that does unit calculations).

Significant figure calculations should have the semantics explained,

e.g., here:

http://chemistry.about.com/od/mathsc...sigfigures.htm
My hope was that the decimal module would provide this functionality,

but:

>>> print Decimal('32.01') + Decimal(5.325) + Decimal('12')
49.335 # instead of 49

>>> print Decimal('25.624') / Decimal('25')
1.02496 # instead of 1.0

>>> print Decimal('1.2') == Decimal('1.23')
False # actually not sure how the semantics should be

I tried to modify the DecimalContext (e.g. getcontext().prec = 2) but

that did not lead to the correct behavior. Google and this list didn't

yield a good answer yet... so I'd be happy to get a good

recommendations or pointers.

P.S. I am aware that significant figure calculation is controversial

and makes implicit assumptions on the probability distributions of the

variables. I am simply looking for an implementation of the (well

defined) arithmetics as defined on the cited website.