|Re: Tiny Challenge: significant digits|
Message #8 Posted by Oliver Unter Ecker on 17 Jan 2012, 6:14 p.m.,
in response to message #7 by Marcus von Cube, Germany
You mean BCD, right? ("Binary arithmetic" sounds like arithmetic with binary numbers...) Sadly, ND1 doesn't have a BCD option yet.
Reals are IEEE-754 doubles in ND1. And the RPL programs above imply reals. (Unlike on the 50g in exact mode, where they imply BigInts. ND1 does have BigInt support, but I chose to not adopt the HP 50g convention (in exact mode only) to regard a decimal typed without a "dot" as a BigInt. Instead, if you want a BigInt, you have to use R->I (or toBig, in "modern" syntax).)
In the latest release BigFloats are supported, too.
« 3 toBigF INV ->NUM ->STR TAIL SIZE »
will actually return whatever the BigFloat precision is set to (40 digits, by default).
To confirm that "1/3*3" is "1" in IEEE-754, just type this in gdb:
Works for any integer-valued double I tried.
Not bad for a format, for which 1.12 is 1.1200000000000001.
(Yes... I'm still yearning for including BCD at some point.)
EDIT: I educated myself and do understand now that with "binary arithmetic" you meant (and correctly termed) what to me is floating-point arithmetic. So, yes, ND1 is using binary arithmetic exclusively, for its Real data type.
Edited: 18 Jan 2012, 3:33 p.m.