ENTER↑ is a misnomer, long live ENTER:

[Raymond Del Tondo]

(07-06-2014 04:38 PM)Katie Wasserman Wrote:  I mostly agree, but just assume have a big, unlabeled key in a different color from all the rest.

That's it. The up-arrow vanished more than a quarter of a century ago, and nearly everyone still found the ENTER/INPUT key, even on an HP-32S or HP-42S:-)

It was clearly distinctable from the other keys, and the manual told how to use it.

The up-arrow was ok in the early years, when HP thought people would need this kind of additional mnemonic. Nowadays the up-arrow would only be a reminiscence to the past.

The colon could be misleading, so better simply omit it.
Keep it simple, keep it ENTER;-)

[Les Bell]

(07-07-2014 10:13 PM)Den Belillo (Martinez Ca.) Wrote:  And remember:
Except for memory size and lines of display; the way the 41 does it is best and right.

Absolutely agree, db! And, of course, this is the way it's been, right since the 35.

While there may be a problem with the way it was explained in the 12C manual - accounting types may well have had exposure to some of the weird adding machine logics out there - it struck me as obvious and intuitive from the time I picked up my new 45 back in 1974. If you understand the stack as X, Y, Z and T, then you have the correct mental model.

From all the comments that number the stack levels and mention RPL, it looks to me as though it's the differences between the RPN and RPL command line and stack behaviours that are causing the confusion. They really are two quite different beasts.

[Les Bell]

(07-07-2014 02:54 AM)Katie Wasserman Wrote:  To this day, I still square like this even on RPN calculators that have an X^2 function (well, unless I'm programming and need the extra stack level or memory space).

I'm the same - although when kakima gave an example using [x^2] in the other thread, I said "yes - that's exactly how I would do it". Reflecting on that, I think there's a difference in how I would do something if just reading left-to-right along an expression without any engagement, vs how I perform a calculation that actually has some meaning and relevance to me. I suspect that might also have something to do with the preference for RPN entry over algebraic - RPN makes more sense when the calculation really has meaning, as opposed to just being something you've got to get through for homework or similar.

[kakima]

I admit x^2 wasn't the best example I could have given. What about 3.7 + ln(3.7) ? Or 3.7 + sin(3.7) ?

I admit these are contrived examples, designed solely to pick on the "never" in the earlier post.

[walter b]

(07-07-2014 09:59 PM)hansklav Wrote:  

(07-07-2014 07:20 PM)walter b Wrote:  How do you know?

Because this is what you wrote in your reply:

(07-07-2014 07:20 PM)walter b Wrote:  (…) ENTER↑ describes what the operation does - it enters a number in the stack. Even the arrow points in the right direction (…)

And you did not mention the other function (digit entry termination).

I didn't mention the obvious. Sorry. I'll be more precise next time I've to explain ENTER↑ on this forum.

(07-07-2014 09:59 PM)hansklav Wrote:  

(07-07-2014 07:20 PM)walter b Wrote:  If you'd take a look to the WP 34S manual instead of telling me what you guess what I see then you'd see how I explain ENTER in the start section ("elementary stack mechanics").

My apologies.

Accepted. Now back to topic:
I agree on that algorithmic picture being a simplified model. But isn't a novice a 'simplified user' as well? And about getting stuck: you're right for a 4-level stack; an 8-level stack as implemented in the 34S and 31S cures this problem for all real world cases.

So I'll repeat: classic RPN with ENTER↑ is a logically consistent operationg method. Certainly it's not perfect (nothing's as perfect as a wheel ) but comes pretty close to it. I concur that there's a problem with what you call the 'RPN Entry' method of some later calcs but that's a different story.

d:-)

Edited to correct a typo.

[Les Bell]

(07-08-2014 04:07 AM)kakima Wrote:  I admit x^2 wasn't the best example I could have given. What about 3.7 + ln(3.7) ? Or 3.7 + sin(3.7) ?

I admit these are contrived examples, designed solely to pick on the "never" in the earlier post.

No problem - your point was fine; those situations do come up, but of course this ENTER isn't optional - it's there to copy the "3.7" on the stack because we want to perform two operations on it without keying it twice. It's something we do without even thinking about it.

[Thomas Klemm]

(07-07-2014 02:54 AM)Katie Wasserman Wrote:  

Quote: But here the HP-35 designers overshot the mark—instead of just having ENTER^ terminate digit entry, they (who knows why?) made it also carry out the unrelated task of duplicating the number into the Y-register, then disabling stack lift.

I don't really know the answer to this, but being an original HP-35 user I thought (and still think) it was to make squaring easier.

According to The Evolution of RPN & Numeric Entry the ↑ key predates ENTER: it did the same as DUP. Entering a number would always overwrite the X register of the stack. The Y register was the accumulator displaying the result of the arithmetic operation.
But the HP-35 has only one line to display. Of course you want to see the result of each calculation. Thus the X register is dropped. But now for chained calculations you had to press two keys for each operation. To calculate 1 + 2 + 3 + 4 you had to key in:
1 ↑ 2 + ↑ 3 + ↑ 4 +
I could imagine that this was considered suboptimal. Instead of overwriting the X register the stack could be lifted when the first digit was entered. However this lifting had to be disabled for the digits that followed.
What about CLEAR x? To keep the same behavior as before entering a number should overwrite the X register: thus lifting the stack had to be disabled.
We still need the first occurrence of ↑ between 1 and 2. Here as well lifting the stack has to be disabled. Otherwise we loose the Z register.

Of course this is just a wild guess.

Cheers
Thomas

[hansklav]

(07-07-2014 10:13 PM)Den Belillo (Martinez Ca.) Wrote:  Hans;
Good thread you started.
RE: Your upcoming RPN tutorial - Show it to us here if you will.

Hi Den,

Finally my RPN Tutorial is in a state that it could serve someone starting to use an RPN calculator. But it is still a preliminary version.

You can find it here: http://hansklav.home.xs4all.nl/rpn/index.html
In case it does not render well on your browser, here is a .pdf version that shows how it should look like (and how it looks like using Mac OS X Safari 6.1.5):
http://hansklav.home.xs4all.nl/rpn/RPN_Tutorial.pdf

As you can see I'm not dogmatic about my ENTER: proposal.
The Tutorial uses the HP-35's ENTER↑ as a paradigm!

Let me know what you think of it.

Hans

Quote:And remember:
Except for memory size and lines of display; the way the 41 does it is best and right.

Last year I acquired an HP-41CX from a Dutch ex-HP employee. It is in nearly new condition! So I share your enthousiasm.