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Didier Lachieze · 09-19-2018, 04:44 AM

A study about the differences between RPN and Algebraic notations: "Electronic calculators: which notation is the better".

It is referenced in PPCJ V7N8p4:

Quote:This five page article is probably the closest "scientific" study available that attempts to determine which is better, AN or RPN. See Applied Ergonomics, March 1980, page2.
The third last paragraph says it all. "In terms of practical choice between calculators, it would appear that RPN is faster and more accurate overall but particularly for more complex problems"

Gamo · (This post was last modified: 09-19-2018 05:05 AM by Gamo.)

Got this article from NASA Lab

"Interruption as a Test of the User-Computer Interface"

Compared RPN and AN

Here is the link to my Dropbox

https://www.dropbox.com/s/d7ayuzxewnzjpo...G.pdf?dl=0

Gamo

Valentin Albillo · 09-19-2018, 05:11 AM

(09-19-2018 04:44 AM)Didier Lachieze Wrote: A study about the differences between RPN and Algebraic notations: "Electronic calculators: which notation is the better".

It is referenced in PPCJ V7N8p4:

Quote:This five page article is probably the closest "scientific" study available that attempts to determine which is better, AN or RPN. See Applied Ergonomics, March 1980, page2.
The third last paragraph says it all. "In terms of practical choice between calculators, it would appear that RPN is faster and more accurate overall but particularly for more complex problems"

The date of the study says it all, 1980.

Things have changed a lot in 38 years. What was true then isn't necessarily true now and matter of fact RPN is but a relic from the past, completely ignored by everyone except a few die-hard fans like us.

V.
.

Didier Lachieze · 09-19-2018, 05:16 AM

(09-19-2018 05:11 AM)Valentin Albillo Wrote: Things have changed a lot in 38 years. What was true then isn't necessarily true now

Sure, but as we are in a museum such articles are not out of place.

Valentin Albillo · 09-19-2018, 05:20 AM

(09-19-2018 05:16 AM)Didier Lachieze Wrote:
(09-19-2018 05:11 AM)Valentin Albillo Wrote: Things have changed a lot in 38 years. What was true then isn't necessarily true now

Sure, but as we are in a museum such articles are not out of place.

Of course not. I was just commenting on the article's conclusion, not the reference itself, thanks for it.

Regards.
V.
.

Maximilian Hohmann · 09-19-2018, 09:27 AM

Hello!

(09-19-2018 04:44 AM)Didier Lachieze Wrote: ...In terms of practical choice between calculators, it would appear that RPN is faster and more accurate overall ...

I was puzzled by the "more accurate" statement. After looking into the article it appears that they actually mean: "less prone to errors" which is something completely different.

Regards
Max

Eddie W. Shore · 09-19-2018, 12:28 PM

With the article's results, it's kind of a double-edge sword why more companies didn't jump on board with RPN in the past.

One one hand, it helped differentiate HP calculators. On the other, less RPN calculators in the market.

Jlouis · 09-19-2018, 12:50 PM

I don't think time has changed the results of the article.

RPN is still RPN and algebraic is still algebraic.

What have changed is calculators with bigger display and the use of the so called "pretty print" or text book entry or whatever, where one can entry in the calculator display an exact expression or formula like in a text book.

But, IMHO, this is good for entry equations. For long expressions number crushing nothing beats RPN and again, the research is still relevant, IMHO.

Thanks for bring this from the past, I was not aware of that, but I've already knew the results by personal experience.

Cheers

JL

**rprosperi** · 09-19-2018, 01:08 PM

(09-19-2018 05:04 AM)Gamo Wrote: Got this article from NASA Lab

"Interruption as a Test of the User-Computer Interface"

Compared RPN and AN

Here is the link to my Dropbox

https://www.dropbox.com/s/d7ayuzxewnzjpo...G.pdf?dl=0

Gamo

Gamo - Every time I try to download (both direct and also to my DB account) the download fails. Is the document shared with the proper settings to allow download?

SlideRule · (This post was last modified: 09-19-2018 01:16 PM by SlideRule.)

From the SUMMARY of INTERRUPTION AS A TEST OF THE USER-COMPUTER INTERFACE by John G. Kreifeldt & Mary E. McCarthy [Dept. of Engineering Design, Tufts University, Medford, MA. 02155] at the 17th Annual Conference on Manual Control

In order to study the effects different logic systems might have on interrupted operation, an Algebraic calculator and a Reverse Polish Notation calculator were compared when trained users were interrupted during problem entry. The RPN calculator showed markedly superior resistance to interruption effects compared to the AN calculator although no significant differences were found when the users were not interrupted.

The 13 page (total) academic research PDF is referenced as N82-13721 and contains many interesting observations/conclusions.

BEST!
SlideRule

Albert Chan · 09-19-2018, 01:31 PM

I think the reason algebraic input cause more "errors" is user doing too much at once.
There is no rule that forbid algebraic calculator to calculate in steps.

This reduces many unnecessary parenthesis groupings, with much simpler sub-expression.
Showed intermediate results allowed some error checking, just like RPN.

This is especially true for EOS calculator, with saved previous calculation in ANS.
Example from the article: (3.3 + 4.5) * (5.2 + 6.1) * (7 - 3 + 8.4) = 1092.936

EOS: (implied ANS when start with +, -, *, /, sqrt ...)
3.3 + 4.5 =
* ( 5.2 + 6.1 =
* ( 7 - 3 + 8.4 =

RPN:
3.3 Enter 4.5 +
5.2 Enter 6.1 + *
7 Enter 3 - 8.4 + *

EOS can scroll back previous calculations, to confirm correct user input.
I think EOS have slight edge overall. Not just me, the market say so too ...

Gamo · 09-19-2018, 01:41 PM

Here is the direct pdf attachment of the article.

Gamo

ttw · 09-19-2018, 01:44 PM

Having taught both high school and college students how to use calculators for math and business classes, I have formed a few opinions. In general, RPN takes about 1/2 the number of keystrokes that algebraic does for the same formula. Second, most students find RPN rather natural; it's the way one evaluates when using pencil and paper. The poorer students found RPN even more natural, probably because they had more trouble with abstract symbols.

Back in the 1960s, outlined the computation tree for some expressions using three-address, two-address, one-address, and stack notation for computation. All four of these did exist in hardware. Three address (like a Cray) was slight better than two-address (IBM 360) which was slightly better than single address (CDC 1604) which was slight better than stack (Burroughs B8500). The B8500 could compile a bit faster. Thus the gain in RPN over algebraic was probably due to notational simplicity, not data flow.

Dwight Sturrock · 09-19-2018, 02:00 PM

Don’t forget the HP12C! It still sells to a unique group with its RPN interface. It’s us engineering & math types that are gradually abandoning RPN.

John Keith · 09-19-2018, 09:06 PM

(09-19-2018 02:00 PM)Dwight Sturrock Wrote: ... It’s us engineering & math types that are gradually abandoning RPN.

Mostly it's the educational world abandoning everything other than TI because TI has a lock on the US education market. "Us engineering & math types" simply aren't enough of a market to have a say in what type of calculators are made and marketed.

burkhard · 09-19-2018, 09:42 PM

(09-19-2018 09:06 PM)John Keith Wrote:
(09-19-2018 02:00 PM)Dwight Sturrock Wrote: ... It’s us engineering & math types that are gradually abandoning RPN.

Mostly it's the educational world abandoning everything other than TI because TI has a lock on the US education market. "Us engineering & math types" simply aren't enough of a market to have a say in what type of calculators are made and marketed.

Well, yes, but then those high school pupils graduate and become university students (some in engineering and sciences), but they keep their old TI graphing calculators. They don't switch over to HP once they take up a technical field of study. HP really does need to stay in the educational market otherwise the gig is up long term. If it were somehow possible to gain something in the school market (if not the US, at least somewhere with some volume), then one can eventually build a following.

When I was in high school (35 years ago), not many peers used HP calculators, but people could easily if they chose, before the mathematics curriculum wasn't wrapped around a specific brand / model like it is now. It's a tough situation in the USA for anybody other than TI.

**rprosperi** · 09-20-2018, 02:59 AM

(09-19-2018 01:31 PM)Albert Chan Wrote: I think EOS have slight edge overall. Not just me, the market say so too ...

The market also chose VHS over Beta. That doesn't mean VHS was better, it simply means there were many more of the inferior products sold. Let's be clear and try to not confuse better or worse with more or less success.

Thomas Klemm · 09-20-2018, 07:17 AM

(09-20-2018 02:59 AM)rprosperi Wrote: Let's be clear and try to not confuse better or worse with more or less success.

Maybe Worse Is Better?

toml_12953 · 09-20-2018, 09:31 AM

(09-20-2018 02:59 AM)rprosperi Wrote:
(09-19-2018 01:31 PM)Albert Chan Wrote: I think EOS have slight edge overall. Not just me, the market say so too ...

The market also chose VHS over Beta. That doesn't mean VHS was better, it simply means there were many more of the inferior products sold. Let's be clear and try to not confuse better or worse with more or less success.

It also means that Sony wanted to charge a license fee to Beta machine and tape makers while VHS was free to use! Beta was actually better quality than VHS.

Maximilian Hohmann · 09-20-2018, 09:56 AM

Hello!

(09-19-2018 02:00 PM)Dwight Sturrock Wrote: It’s us engineering & math types that are gradually abandoning RPN.

We've had this topic dozens of time before, yet I repeat my little point again: In my part of the world and during the years it would have mattered to me, the "engineering&math types" who were high school, college and university students simply could not afford RPN calculators. For some reason only known to HP they chose to market their products at two or three times what the competition asked for theirs. Had, in the all-important period between 1975 and 1985, HP sold their RPN calculators at the same price level as Ti, Casio and everybody else, then maybe today high school students would use HP. The question "which one is better" never mattered.

Regards,
Max

NB: And I still fail to see why, using an RPN calculator, one solves a problem exactly as one does with paper and pencil. Not me. Maybe because I learnt how to do calculations with pen and paper from teachers who never could afford RPN calculators themselves?