|Re: 12C Classic Simulator for iPhone version 2.0 released|
Message #2 Posted by Eric Smith on 29 Oct 2008, 5:53 p.m.,
in response to message #1 by Les Wright
It's a fine product, but it appears to use native binary IEEE floating point, rather than BCD. It definitely doesn't seem to use the same financial algorithms as the real 12C. Trying to work Kahan's example, "60 ENTER 60 * 24 * 365 * n 10 RCL n / i 0 PV 0.01 CHS PMT FV" gets a result fairly close to that of the real 12C, but then pressing "i" to back calculate the interest rate as a check returns 100.8, rather than the correct answer near 0.0000003171.
It also doesn't implement the program instruction with the keycodes "45, 43 31", which FIN-12C does. Of course, most people never use that or even know that it exists.
FIN-12C costs twice as much, but uses BCD arithmetic with the same algorithms as the real 12C, so it will produce numerically identical results.
Edited: 29 Oct 2008, 9:20 p.m. after one or more responses were posted