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on the RPN mentioning sharp pc-1211, v.albillo, el-506w and recurring topics
12-03-2017, 06:54 PM
Post: #1
on the RPN mentioning sharp pc-1211, v.albillo, el-506w and recurring topics
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

n2: see hp calc torrent or the post of Dave F.

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: and

and .
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.

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.

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on the RPN mentioning sharp pc-1211, v.albillo, el-506w and recurring topics - pier4r - 12-03-2017 06:54 PM

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