|Re: Why chain logic? some history and an example.|
Message #6 Posted by Gene Wright on 7 Aug 2008, 11:59 a.m.,
in response to message #1 by Martin Pinckney
Couple of thoughts:
The 17b predates Cyrille and all other current HP calculator individuals, so they should get a pass on why the 17b used algebraic without precedence.
Having taught in business schools all during the late 1980s through the early 2000s, I can say how badly non-RPN HP business calculators performed for students compared to the TI offerings when doing any sort of non-trivial calculation. TI could be set to chain or AOS (non-precedence or precedence). HP only offered chain.
Example: If you deposit $1000 into a savings account paying 6%, compounded monthly, how much will be in the account after 5 years.
Solving this WITHOUT using the TVM functions required these keystrokes on the chain HP 10b:
1000 x shift ( shift ( 1 + shift ( 0.06 divide 12 shift ) shift ) shift Y^X 60 =
That's 29 keystrokes if I counted correctly.
On the TI competitor, the keystrokes were (in AOS mode):
1000 x ( 1 + 0.06 divide 12 ) Y^X 60 =
Total of 20 keystrokes.
It was no wonder I had students throw away their HP 10b models and go buy the TI alternative.
[EDITED] For years I begged for algebraic with operator precedence on an HP ** financial calculator ** model.
The HP 20b offers all three modes... RPN (woohoo), chain (for Cyrille's dad - kidding Cyrille!) and algebraic with precedence. I don't see the 20b continuing any legacy with the HP 17b, since it offers chain and algebraic. Chain is probably offered for comparison with TI as well as for "less sophisticated users".
This is a fantastic change and a welcome one.
P.S. As to why HP made calculators (and still does) that have a chain logic system... TI apparently thinks business users might want to use chain logic too, since it is present on all their business models. But at least they have almost always allowed a choice of modes, something that HP has at last provided. Way to go HP!
Edited: 8 Aug 2008, 8:54 a.m. after one or more responses were posted