9999999999999999.0 – 9999999999999998.0

Post by sgt101 » Sun, Jan 06, 2019, 8:40 AM UTC

twtw wrote: post #46

seanalltogether wrote: post #13

Are there any mainstream languages that consider a decimal number to be a primitive type? I feel like floating point numbers are far less meaningful in every day programs. Even 2d graphics would be easier with decimal numbers. Unless you're using numbers that scale from very small to very large, like 3d games or scientific calculations, you don't actually want to use floating point.

Julia has built in rationals (as do a few other languages). I'm not aware of any language (other than Wolfram) that defaults to storing something like 0.1 as 1/10 - i.e. uses the decimal constant notation for rationals, rather than having some secondary syntax or library.

Post by erpellan » Sun, Jan 06, 2019, 9:13 AM UTC

lenticular wrote: post #52

twtw wrote: post #39

I don't understand all the crap that IEEE 754 gets. I appreciate that it may be surprising that 0.1 + 0.2 != 0.3 at first, or that many people are not educated about floating point, but I don't understand the people who "understand" floating point and continue to criticize it for the 0.1 + 0.2 "problem." The fact is that IEEE 754 is an exceptionally good way to approximate the reals in computers with a minimum number…

Yeah, the limitations of FP are well-known to anyone who does much numerical work. Floating point numbers are the optimal minimum message length method of representing reals with an improper Jeffery's prior distribution. A Jeffery's prior is a prior that is invariant under reparameterization, which is a mandatory property for approximating the reals. In this case, it is where Prob(log(|x|)) is proportional to a const…

Post by johndough » Sun, Jan 06, 2019, 9:30 AM UTC

bjourne wrote: post #125

saagarjha wrote: post #96

Earlier quoted context omitted.

Rationals get unwieldy quickly, even with the simplest of arithmetic. A couple of additions is enough to get a large denominator.

That has not been my experience using a language with builtin support for rationals. The rational is simplified after each operation so it never grows unwieldy large. It is slower than floats, but imo vastly superior for most use cases.

Post by minitech » Sun, Jan 06, 2019, 9:34 AM UTC

tzury wrote: post #215

With python, I get 2 even when using Decimals. Python 2.7.3 (default, Oct 26 2016, 21:01:49) [GCC 4.6.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> from decimal import * >>> getcontext().prec 28 >>> a=Decimal(9999999999999999.0) >>> b=Decimal(9999999999999998.0) >>> a-b Decimal('2') That is unexpected.

Post by Steve44 » Sun, Jan 06, 2019, 9:49 AM UTC