on the RPN mentioning sharp pc-1211, v.albillo, el-506w and recurring topics

[pier4r]

Due to the topic about the most common calculator in the forum (n1) I wanted to read about the hp41 that is so far the clear winner of the survey. A user suggested, among other readings about the hp41, a writing of Valentin Albillo "A new contender" (datafile27, see n2).

I read it and it is a quite pleasant article that put in perspective the abilities of the hp41, the then "hp flagship", and the sharp pc-1211, not only a calculator but quite a pocket computer provided with a basic interpreter.

That let me reflect again on my position about the RPN. I was first exposed to RPN (well, its successor, RPL. See n3) with the hp 50g in December 2010. I was a bit disappointed since RPL/RPN was (is) not that intuitive compared to the procedural languages that I used in 2010 (and even today).

Digging in this forum I read countless of threads about RPN vs algebraic. Nonetheless every new thread brings every time something new, although with decreasing marginal utility. So here it is another RPN vs algebraic (well almost) entry. Side note: Reading old threads is an activity that I recommend if you are relatively new. It takes weeks and months, but it is nice. You will discover that another common topic is about accuracy and guard digits, see n4.

I can appreciate that RPN is more user friendly, once one get a grasp on it, compared to algebraic calculators that do not show what one typed up to that point. Without knowing how many parentheses are open, or if I made a mistake, as V.Albillo writes, one has to write the formula from scratch. In RPN one can save himself earlier.

Anyway once one has a display where one can see the expression that he is typing (see the sharp pc-1211 or the sharp el-506w that has several of those nifty editing features present in the 1211), I think that algebraic is way more natural to use. Simply because one can just insert the equation as one writes it down on paper. Raise your hand if you write your equations in RPN form also on paper. I don't.

It is not that the notation I use to write is inherently better, otherwise all the languages written right to left would be wrong (Arabic, Hebrew and maybe others). It is a matter of habit. At least in the western world - for what I know - formulas are written down by people in algebraic form and not RPN. Therefore we are more geared to manipulate algebraic objects.

I read several passionate post about the advantages of RPN in this and other forums, but the arguments were never that solid for me. At the end those could be summarized by "Engineers compose the formula on the fly while typing, especially on the field, so RPN is more versatile for the job".

The only strong argument pro RPN that I ever read (over and over) is pragmatical.
RPN simplifies the work that the calculator has to do in interpreting the input compared to an algebraic entry (see n6). Therefore less complexity, less circuits and so on. This is especially true for earlier calculators, although I read of real problem solving feats, see n5.

In conclusion, I understand that RPN was a good tradeoff for the first calculators and then, having built a community with solutions and habits, was left in the subsequent machines. But I think that for someone ready to change course (or someone new), the algebraic entry offered by a sharp pc-1211 or a relatively new sharp el506w, would be more fruitful to pick up and use.
Though algebraic entry without "seeing the formula", like the ti34 from 1987, are not that easier compared to RPN. Especially with long formulae.

That said, I pick the umbrella and prepare for the incoming sheepstorm.

## notes
n1: http://www.hpmuseum.org/forum/thread-9594.html

n2: see hp calc torrent or the post of Dave F. http://www.hpmuseum.org/forum/thread-909...l#pid84103

n3: Yes I know. To my surprise even in a small community like this there are factions RPN and RPL. When for me are both very similar if one disregards the extensive library of additional commands for RPL. Has anyone replicated a RPN program in RPL limiting himself to simple STO/RCL/SWAP and function procedures ?

n4: two quick examples: http://www.hpmuseum.org/forum/thread-9610.html and http://www.hpmuseum.org/forum/thread-1309.html

n5:
http://files.righto.com/calculator/sincl...lator.html
and
https://hackaday.com/2013/08/30/ken-shir...nt-1483801 .
Interesting the quote (that will be lost when the page above will be lost :/)
"Toward the end, reducing the code became incredibly difficult; I was spending many days – and nights – searching for ways to reduce the code by even a single instruction."
That reminds me of the RPN acrobatics to save here and there one step or 3 bytes. Very common and impressive in the challenges posted here.

n6: http://www.hpmuseum.org/forum/archive/in...-1374.html
At Hewlett Packard we were so proud that our calculators, the first scientific ones ever, were years ahead of competition. They used postfix partly because the least logic or ROM chips were quite expensive back then. It would have taken extra keys and an infix to postfix translator to use infix. Also, a larger and more expensive desktop HP machine from the division in Colorado Springs used postfix, for the same reasons. The HP-35 was an attempt to miniaturize this machine.

[Maximilian Hohmann]

Hi!

(12-03-2017 06:54 PM)pier4r Wrote:  That said, I pick the umbrella and prepare for the incoming sheepstorm.

Don't worry, you are not the only heretic in this forum. As you have read the old threads you may have seen that I already confessed several times that I am really a Ti person. My Ti59 got me through the last part of school and university with ease and I never found it mor difficult to remember how many parentheses I had already opened than which part of the equation I pushed onto what level of the stack.

But as you say, RPN is closer to the machine and certainly results in less keystrokes and therefore shorter programs - a big advantage in the days when memory was a precious resource. But those days came to an end before the mid 1980ies.

If I ever need a calculator at work again (right now the only one I really use is a smartphone App called "Flight Time Calculator" which prevents me from mistakes when I fill in the technical aircraft log after a long day) it will be algebraic one with a dialect of BASIC, just like a Ti89 or Voyage 200 (if size does not matter).

Regards
Max

[Trond]

Wait a second. You can see everything you type in HP35S, which also uses algebraic notation as an alternative. I just tried this calculation in both (don't do any of it in your head of course):

(7+12)x(5+23)
(3+18)x(4+12)

I know this is personal and not very scientific, but that calculation is way faster in RPN for me at least. I did a similar calculation, for an actual assignment, in front of my students (who all have modern algebraic calculators), and their jaws dropped. Most of them still prefer algebraic, simply because they can't wrap their heads around RPN

[pier4r]

(12-03-2017 07:43 PM)Trond Wrote:  (7+12)x(5+23)
(3+18)x(4+12)

As I wrote. If I cannot see the formula I am typing, I don't find the RPN bad. (and even if I can type, you are right, fractional formulas are not that easy too type too)

Anyway I would first do the numerator, then ANS / (denominator) .
In algebraic.

In RPN would be quite similar.
7 12 + 5 23 + *
3 18 + 4 12 + *
/

My point is though, aside from some edge cases, it is easier to follow the written form. In RPN I have to rework it in my mind.
First I extrapolate what I need first, then I proceed with the rest. This is surely a pedagogical advantage, but after a while it is just overhead for my point of view.
Why is it overhead? Because I do not write the formula in RPN. I am not geared towards it when I manipulate the formula on paper. You yourself wrote in algebric form to communicate with me and the rest of the forum, not in RPN directly.

[Maximilian Hohmann]

(12-03-2017 07:43 PM)Trond Wrote:  I just tried this calculation in both (don't do any of it in your head of course):

...

I know this is personal and not very scientific, but that calculation is way faster in RPN for me at least.

I just did the same using an Hp-35s which happened to lie on my desk. Personally I am faster using the algebraic variant, firstly because I am more used to it and and also because on this calculator I can see almost the whole "equation" in the display. Since the calculator inserts the ")" on it's own, the number of keystrokes is about the same. In RPN I have to press "Enter" several times, in algebraic mode I have to press "(" and "right arrow" to get out of the parentheses. I guess it really depends on your background. On my Ti59 I could only see the last number and still was able to calculate complicated stuff. Back in those days of course :-)

[Trond]

(12-03-2017 07:58 PM)pier4r Wrote:  

(12-03-2017 07:43 PM)Trond Wrote:  (7+12)x(5+23)
(3+18)x(4+12)

As I wrote. If I cannot see the formula I am typing, I don't find the RPN bad. (and even if I can type, you are right, fractional formulas are not that easy too type too)

Anyway I would first do the numerator, then ANS / (denominator) .
In algebraic.

In RPN would be quite similar.
7 12 + 5 23 + *
3 18 + 4 12 + *
/

My point is though, aside from some edge cases, it is easier to follow the written form. In RPN I have to rework it in my mind.
First I extrapolate what I need first, then I proceed with the rest. This is surely a pedagogical advantage, but after a while it is just overhead for my point of view.
Why is it overhead? Because I do not write the formula in RPN. I am not geared towards it when I manipulate the formula on paper. You yourself wrote in algebric form to communicate with me and the rest of the forum, not in RPN directly.

So we seem to be contradicting each other here. I said that you CAN see the formula as you type it in 35S and you seem to say that you cannot. So by "seeing" you mean seeing it exactly like I typed it above? Sure, that is always a neat option, but somehow I don't find it faster or more convenient (it wasn't when I typed it here, I had to think about how to represent the division with underlining text. Ha ha . But yes, that's how I would write it if I did it with a pen). Maybe it's just the way my head works, since I learned RPN at an early age, but to me RPN goes faster when pressing buttons, no matter if I see it or not.

[pier4r]

the topic is not much about "what Trond find best" or not. But it is about "what seems more fitting the general trend".

Unless one writes on paper:

5 3 + *

I find that the trend is geared towards algebraics. There are cases - as wrote above - where the RPN is as good or even better, but not with the current multiline calculators.

@Trond: my point about writing the formula was a bit different. If I use a device that shows easily the formula while I type it, I go with algebraic notation. I do not see the need of RPN in that case. If I cannot see the formula, then RPN has practical advantages.

If I see an algebraic formula built while I type RPN, it is even more confusing.

On the 50g either I use the equation writer (so no RPN), or I use the RPN entries but for smaller formulas. Maybe 3-4 operations.

[Maximilian Hohmann]

(12-03-2017 08:39 PM)pier4r Wrote:  On the 50g either I use the equation writer ...

If you have an evening (or an entire week...) to spare you might want to try out the equation writer of the 48 series ;-) I think even the hardcore fans of those calculators will have a hard time finding any good points about that piece of software.

Saluti
Max

[pier4r]

(12-03-2017 08:44 PM)Maximilian Hohmann Wrote:  If you have an evening (or an entire week...) to spare you might want to try out the equation writer of the 48 series ;-) I think even the hardcore fans of those calculators will have a hard time finding any good points about that piece of software.

I am not sure I understand. You mean the built in equation writer of the 50g is not that good? (It should come from Erable or something like that from the 48)

Surely it takes time to write something with the equation writer. But the tradeoff is that I am pretty sure (and delighted) with what I write.

For quicker stuff there is the el 506w.

[Maximilian Hohmann]

(12-03-2017 09:13 PM)pier4r Wrote:  I am not sure I understand. You mean the built in equation writer of the 50g is not that good?

No. But the equation writer of the 48 is incredibly bad. So bad that there is really no point in using it. It should be used as an example on computer science courses on how not to design a user interface. Unless of course one grew up with it and got to love it before seeing different solutions.

[pier4r]

(12-03-2017 09:42 PM)Maximilian Hohmann Wrote:  No. But the equation writer of the 48 is incredibly bad. So bad that there is really no point in using it. It should be used as an example on computer science courses on how not to design a user interface. Unless of course one grew up with it and got to love it before seeing different solutions.

Interesting point of view. Would it be possible for you to point to a similar equation writer that is "slick" ?

I know only the autocomplete/autocorrect in word (from 2007 onwards) using the UTN notes (n1) that once one sets up it properly, is quite fast.

Way faster than my attempts with latex.

n1: http://unicode.org/notes/tn28/

[Maximilian Hohmann]

(12-03-2017 09:47 PM)pier4r Wrote:  Would it be possible for you to point to a similar equation writer that is "slick" ?

Try Mathematica or Wolfram Alpha (online) for a start. You don't really need to bother about "writing" your equations, the system is smart enough to understand what you mean.
Myself I was using a software called "Interleaf" in the late 1980ies/early 1990ies to write technical papers which had a phantastic (for that era) equation editor. Around the time the 48 was developed.

[Steve Simpkin]

(12-03-2017 09:47 PM)pier4r Wrote:  

(12-03-2017 09:42 PM)Maximilian Hohmann Wrote:  No. But the equation writer of the 48 is incredibly bad. So bad that there is really no point in using it. It should be used as an example on computer science courses on how not to design a user interface. Unless of course one grew up with it and got to love it before seeing different solutions.

Interesting point of view. Would it be possible for you to point to a similar equation writer that is "slick" ?

I would say *any* modern implementation of a "Textbook" display calculator would be better in every way than the original HP-48 "Equation Writer". The Equation Writer in the original HP-48SX/S was *extremely* S-L-O-W and very awkward to navigate around in and use. It was a separate environment that was strictly limited to returning the results of the "textbook" equation you laboriously wrote back to the stack as an in-line (ugly) algebraic equation (or vice versa). Even Bill Wickes admitted that it pushed the absolute limits of that machine's hardware. While it may have been useful in certain cases, it was usually much faster to just enter the algebraic equation as a single in-line algebraic in the command line.

The Equation Writer built into the HP-48GX/G was slightly improved and was faster, but still very limited. The HP-49G finally implemented an integrated CAS environment (based on ALG48 and Erable) that allowed you to calculate with and display "textbook" results. The HP-50G improved upon this and made it much faster. These final two evolution's brought about what we think of as having a "Textbook" display in a modern CAS calculator.

[AlexFekken]

RPN is for people who never, ever make mistakes so that they do not have to edit, or even see, a completed formula and who get a kick out of editing a program while seeing only one instruction at a time. I know because I used to be like that myself. :-) And, to be more serious, when I bought my HP 67 in 1977 or so, RPN was of course vastly superior to any alternatives.

Now that I have grown up (and/or old) and I am making more and more mistakes every day, such as engaging in religious discussions like this one, as well as having to maintain the produce of others, I generally prefer readability and maintainability over squeezing out as many bytes and/or keystrokes as possible.

So although I still have a number of RPN devices (and will get a DM42 for kicks) and I appreciate and admire the clever work done by the many RPN heroes that are still out there, my favourite calculator is the HP Prime. In non-RPN mode, using textbook input etc, i.e. like a real wuss and proud of it...

[toml_12953]

(12-03-2017 06:54 PM)pier4r Wrote:  I read several passionate post about the advantages of RPN in this and other forums, but the arguments were never that solid for me. At the end those could be summarized by "Engineers compose the formula on the fly while typing, especially on the field, so RPN is more versatile for the job".

The only strong argument pro RPN that I ever read (over and over) is pragmatical.
RPN simplifies the work that the calculator has to do in interpreting the input compared to an algebraic entry (see n6). Therefore less complexity, less circuits and so on. This is especially true for earlier calculators, although I read of real problem solving feats, see n5.

I actually like both! Algebraic is the way I'd write the expression but RPN is the way I'd manually solve the expression. Write down an expression in algebraic. Now manually solve it. I'll bet you use RPN and use PMDAS to solve within parentheses calculating the inner parentheses first then combining the sub-expressions to work outward.

Example: Solve

(4+7) * (6+2)
----------------
(3+5) * (9+3)

You'd probably calculate 4+7 and 6+2 then multiply them to get 88. Then you'd calculate 3+5 and 9+3 and multiply them to get 96. Finally, you'd do the division and get 0.9167...

This is the same way you'd solve the expression using an RPN calculator.

[Garth Wilson]

I have come to be of the opinion that it partly depends on what kind of brain you were born with. I seem to have an RPN brain. Besides my 41cx which I use every day, I have the HP-71B as well, and I do not feel at home at all with its BASIC for doing calculations, even though I used it heavily for five years. I don't ever want to use a non-RPN calculator again.

[pier4r]

(12-04-2017 08:54 AM)toml_12953 Wrote:  I actually like both! Algebraic is the way I'd write the expression but RPN is the way I'd manually solve the expression. Write down an expression in algebraic. Now manually solve it. I'll bet you use RPN and use PMDAS to solve within parentheses calculating the inner parentheses first then combining the sub-expressions to work outward.

Example: Solve

(4+7) * (6+2)
----------------
(3+5) * (9+3)

You'd probably calculate 4+7 and 6+2 then multiply them to get 88. Then you'd calculate 3+5 and 9+3 and multiply them to get 96. Finally, you'd do the division and get 0.9167...

This is the same way you'd solve the expression using an RPN calculator.

Nice point. RPN is quite similar how I compute the fraction. That I never read it exposed in this way.

Indeed I would do:
4+7 (so this in algebraic, but it is small enough to apply RPN too)
6+2
*
3+5
9+3
*
/

[franz.b]

(12-04-2017 11:50 AM)Garth Wilson Wrote:  I have come to be of the opinion that it partly depends on what kind of brain you were born with. I seem to have an RPN brain. Besides my 41cx which I use every day, I have the HP-71B as well, and I do not feel at home at all with its BASIC for doing calculations, even though I used it heavily for five years. I don't ever want to use a non-RPN calculator again.

I agree. I started using algebraic calculators in middle school, up to a fx-8000g with which I concluded the technical institute in mechanics. At university I used a 48s rpn and I found it fantastic. Now after years I restarted studying physics again but the hp48 no longer works for the keyboard problem, so I picked up the algebraic calculator of the guys but I was about to throw up ...
I bought a 50g and I'm rejuvenated for 20 years: my brain is RPN

[Trond]

(12-03-2017 08:39 PM)pier4r Wrote:  the topic is not much about "what Trond find best" or not. But it is about "what seems more fitting the general trend".

Well......notice how many personal opinions and points of view you give here (e.g. you find this or that confusing). We all have a tendency to think that our own opinion reflects some sort of general truth. We're not discussing some physical constant here. It is all personal opinion.

[Maximilian Hohmann]

(12-04-2017 04:32 PM)Trond Wrote:  We're not discussing some physical constant here. It is all personal opinion.

Well.... I would estimate that the fraction of RPN calculators among the total worldwide pool of calculators is about the same than the followers of the flat-earth-theory among cosmologists ;-) So yes, personal opinion to some degree, but history has cast a clear vote in that respect. And the day when HP stops making calculators (which all of us will see come I'm afraid) RPN will be over for good, apart from us die-hards.

Personally I am bilingual in that respect but see RPN a bit like Latin which I had to study at school. A very logical language and the basis for many modern languages, but otherwise pretty much defunct.