ruby floating point calculations

rubyonrails-talk
1

helo eveyone,

for a rails app i’m working on i need to do some calculations with some floating point data. the calculations aren’t on currency so i can’t do the trick where you do the math with integers and have the units in pennies. i would like the results to be as accurate as possible with the least amount of work (haha). any suggestions? is there a ruby gem for more accurate float calculations?

thanks in advance,

stuart

2

Define accuracy. What are you doing here?

3

calculating ratios mostly, but some other stuff too. for my purposes accuracy would be calculations being accurate to .001 .. i guess i probably just could premultiply the values i'm going to use with 1000 to account for the precision i'm trying to get and divide by 1000 after.. to tell you the truth i'm not sure how bad the floating inacuracy is generally.. but i remember seeing some calculations that were pretty far off

4

Ah, sounds like you want to use Rational: http://www.ruby-doc.org/stdlib/libdoc/rational/rdoc/index.html

You can also use BigDecimal (require 'bigdecimal').