06-07-2006, 02:23 AM
Does anyone know why 40gs has x^y ? 50g has y^x again.
Cannot name any of both exponentiation keys "traditional", because hp35 had x^y d:)
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x^y and y^x
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06-07-2006, 02:31 AM
The HP40GS is an algebraic-entry calculator whereas the HP50G is an RPN-entry calculator.
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06-07-2006, 04:25 PM
Quote:You are right for sure. But I don't comprehend why this shall be a reason. Please explain for me dummy.
Edited: 7 June 2006, 4:37 p.m. ▼
06-07-2006, 05:51 PM
The x and y refer to the order of input. That is, the x is the first argument, and the y is the second argument (using a natural lexicographic ordering). For the algebraic x^y: Since algebraic notation is essentially the same as what you see, x^y means just that. That is, if you see 2^3, you enter in 2 [x^y] 3. With algebraic notation, it's first-in-first-out. So if your inputs are 2 and 3, the first argument is the 2. For the RPN y^x: Since RPN uses a last-in-first-out (i.e. the last input is the first argument) model, it is natural to use (for a 2-level stack) "y" for the second level and "x" for the first level (this is just a lexicographical ordering). We still enter the arguments the same way. That is, if we want to compute 2^3, we would still enter in 2 followed by 3. But this puts 2 on level two (y) and 3 on level one (x). So the ^ command, in order for its label to properly reflect the correct input paring, is called y^x and not x^y due to the input method of last-in-first-out (hence the R in RPN -- it stands for reverse). I hope I did not muddy up the waters even more with that poor attempt at an explanation.
Edited: 7 June 2006, 5:58 p.m.
06-07-2006, 03:16 AM
Quote: For RPN, y^x is definitely traditional. The 35 was one of the first RPN calculators, and the details of RPN hadn't yet completely solidified. So the 35 predates the tradition.
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06-07-2006, 04:04 AM
I thought the variable names were chosen according to the stack convention. On a 35, you really have to enter the exponent first and the base second (which is then located in the x register). AFAIK it was designed this way to compensate for the missing 10^x function or is this a legend? ▼
06-07-2006, 04:28 AM
Quote: Yes; that doesn't contradict what I said. The 35 predates the "traditional" RPN y^x function. The tradition was established with the 45, 65, etc.
06-07-2006, 10:45 PM
Quote: I would say that this is the most plausible explanation -- i.e., to raise an entered x-value to a power of 10, just do 10 xy. Another possible explanation is that "xy" was thought to be more intuitive, since y is above x in the stack. Unfortunately, that convention differs from the subtraction and division operators, which perform "y minus x" and "y divided by x", respectively. "y raised to power of x" is certainly more consistent.
Speaking of 10x, it was thoughtful of HP to make LN and ex unshifted keys on the Pioneers, with LOG and 10x both shifted. The "base-e" functions are used much more frequently than the "base 10" functions. On the previous models -- HP-41 and Voyager-series HP-10C, HP-11C, and HP-15C -- these functions were placed differently, most likely by deliberate intent:
One more thing: yx and 1/x are side-by-side on the Voyagers, and on the same key (with yx shifted) on the HP-41. Why? This facilitates using the two functions together to execute the root function y1/x. That's thoughtful attention to detail! You won't find it on the mass-market calculators of today -- their designers don't have a clue... -- KS
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06-08-2006, 05:31 AM
Quote:
Wow! I didn't pay so much attention to this kind of details! -- Antonio
06-08-2006, 07:18 PM
Karl, thanks for pointing to the design details reflecting the thoughtful and careful work of the engineers who layed out the vintage models. There's quite some hidden beauty in those items. One more reason for using and collecting them - and only them. In an humble attempt to transfer and extrapolate this into our time, where display technology has reached a far higher level and memory is readily available, here are 2 proposals I ask for your votes, please. I did these layouts more as a mental exercise than believing in an immediate application. Perhaps somebody cares - maybe even HP is listening or somebody else interested in this topic. After all, the density of such folks is at least elevated in this forum. And it is frequented by many more nerds than other sites (if those are up at all ;) ). Both proposals are based on the Voyagers and will keep their size. Contrasting colors are used for different classes of operations (white, blue, gold, orange, and green on a dark background - better to read than any "platinum"-scheme I know). As many functions as possible can be accessed directly using 3 prefix keys (because I find it hard to remember where an invisible function is hidden), the rest is stored in menus. You will find consistent patterns of direct and inverse functions. Related operations, functions or menus, are placed next to each other. Both layouts feature a QWERTY keyboard, too. Menu names often start with the letter becoming effective in alpha mode at the same key. And SPACE and TIME will be treated with one key ;) Both proposals combine the full set of features of the 42S and the 16C with minor contributions from other newer and older models as well. Keys are labeled in a way they can be used in different modes, e.g. x^-1 will calculate 1/x for real numbers, invert a matrix or flip the bits of an integer. Another example is ^, acting as y^x for real numbers and "up arrow" in alpha mode. Or |x| returns the absolute value of a real or complex number, eliminates the sign of an integer, calculates the length of a vector or the norm of a matrix.
The main difference between both layouts is one has the traditional vertical ENTER
while the other one features an horizontal ENTER key, innovative for Voyager-like models: So which one is your favourite? May I ask for your votes, please? ▼
06-09-2006, 10:53 AM
I vote for the first one (with the vertical [ENTER]. I think that looks much nicer on a Voyager-style layout (which is my favorite HP style, BTW).
06-09-2006, 11:33 AM
The second layout is better in my opinion: much more consistent with the horizontal large ENTER key in every HP calc apart from the Voyagers, and since it serves as a SPACE key too... central and horizontal is nice!
06-09-2006, 10:29 PM
Walter -- I congratulate your efforts in development of advanced calculator models on the Voyager-series platform. Utilizing a longer display with a sharp dot-matrix LCD for equations, complex numbers, and more menu options is an idea I had, as well. My basic assessment, though, is that your concepts are overambitious -- there's too much diverse functionality crammed into a limited package. Thus, the crisp, organized and cohesive layout of the Voyagers is not replicated. My main comments:
Well, I could go on, but I think you see the point. Cramming an HP-42S, HP-15C, HP-16C, HP-12C (TVM) and HP-32SII (equations and fractions) coherently into a Voyager-series package is a daunting task, indeed. I've thought about how to meld the HP-15C and HP-32SII into a compact, non-graphing unit, and haven't yet been able to crystallize the concept... I've posted a discussion extolling the HP-15C layout (derived from the HP-11C), which is as close to perfection as has ever been achieved. Readers should keep it in mind when designing conceptual calculators -- I've yet to see one that meets the high standard. Cheers, -- KS
Edited: 10 June 2006, 2:11 a.m. ▼
06-11-2006, 12:54 AM
@All, thanks! Now it's Horizontal 1, Vertical 1. Which team will score next? @Karl, thanks for your elaborate response. It deserves a detailed answer you'll get later. For now: I must admit I rated the value of a QWERTY alpha keyboard rather high. Whenever you want to type more than just one English word, it's the fastest entry method, because everybody knows it. So, many of your points can be attributed to this decision, since I wanted a menu to appear at the position of the corresponding letter. I may drop this requirement for a more cohesive *calculator* layout and give the QWERTY as a separate bonus. Just to clarify the 3d: This is meant for stats and coordinate transformations, only. Graphs shall be confined to simple 2d function plots. If such graphs can be displayed on a 42S or 28C, they must be possible here, too. That's all for now. Thanks again.
Walter Edited: 12 June 2006, 6:42 p.m.
06-13-2006, 08:14 AM
Karl, My remaining answers to your comments:
Quote:Thanks for your advise. Will be changed.
Quote:Please look at Blackberry, Nokia, etc. – they all use QWERTY. For size reasons, these keyboards are never conventional, but most people still find the letters intuitively. ABCD is not suited to write words or sentences. Dvorak may be intuitive, but only a minute fraction of the population of the world work with it. If you require need for a scientific calc and knowledge of Dvorak keyboards, you’ll end up with less than ppm (will be different for the Czech composer ;-) )
Quote:Here I definitively disagree. Sigma+ is used frequently, and Sigma- is the inverse also needed for error recovery. You find them on every keyboard of a scientific since the HP45.
Quote:HP15C had a panel of 111 operations (39 keys + 36 shifted operations with 2 prefix keys) and contained >130 built in functions. HP42S had a panel of 73 operations (37 keys + 36 shifted operations and contained >350 functions, so functions like hyperbolics were placed in menus you had to remember. I agree with you to have them visible on the panel is better than to bury them in a menu. The limit of 39 keys may require trigonometry shifted, however, because other functions may be more important to appear on the key tops. In your remaining comments, you criticize consequences of my intention to have e.g. STAT at the position of the letter S and PROB at P. As admitted already, this was less than optimum. I will change it.
Quote:That exactly is the challenge. Regards, Walter
06-10-2006, 01:41 AM
All -- Recently, a few contributors have developed images of faceplates for conceptual scientific calculators, based on the Voyager and Pioneer platforms. Anyone who undertakes such an effort ought first to fully appreciate the careful thought and attention to detail encomapassed in the organization of its functionality on the HP-15C keyboard, and try to match that in his own concept. While the cohesiveness and completeness of that functionality alone is impressive (as documented by Valentin Albillo in "Long Live the HP-15C" and short essays in the MoHPC Forum), I will describe how meticulously crafted the keyboard arrangement really was. Its impeccable organization adds value by making any function easy to find, thus saving time and effort. Thoughtful layout was very important, because the lack of an alphanumeric capability to allow softkey menus and named commands dictated a direct placement of every function on the keyboard. The HP-15C was developed from the fine HP-11C, augmented by extensive amounts of advanced functionality in the same compact package. HP even managed to slightly improve the layout while "shoe-horning" the new functions. An article in the May 1983 Hewlett-Packard Journal, "Scientific Pocket Calculator Extends Range of Built-in Functions", describes the engineering effort. (A scan of this article is available for purchase on CD #3 or DVD from the MoHPC.) This is a case where annotated pictures would certainly help to illustrate, but I'll just provide links to two unmodified photographs against which to verify my descriptions: http://www.hpmuseum.org/15.jpg http://www.hpmuseum.org/11c.jpg One thing that stands out in these photos: The keyboard and faceplate do not look cluttered, despite the abundance of functions. This is because the two shift colors (yellow and blue) contrast well with both the faceplate and each other. Also, the beveled keys allow the blue shift functions to be printed directly on the keys, right below the primary key legends. Thus, everything is neatly arranged, with plenty of space between rows. (Compare that with an HP-33S!) Here are the compact and coherent functional groupings I've identified on the HP-15C keyboard layout, which can readily be seen in the photo:
The HP-15C functions DIM, MATRIX, RESULT, x<>, SOLVE, INTEG, TEST, and Re<->Im replaced six conditional-test operations along with x<>I and x<>(i) from the HP-11C. This provided the following new functionality and improvements:
This excellence of design was made possible only by the careful thought and concerted effort that went into the HP-15C and its immediate predecessors, the HP-11C and HP-34C. These attributes are not particularly evident in the calculators and consumer-electronics products of today -- most of which are not intended to be enduring devices for long-term use. But, we should keep them in mind when using Photoshop or other software for our own concepts. -- KS
Edited: 11 June 2006, 8:00 p.m. ▼
06-12-2006, 03:28 AM
This is the most thorough and precise description of a calculator keyboard layout I've ever read, and it pictures exactly what I feel when I see the proposals for new "Voyager" or "Pioneer" style calculators (e.g. OpenRPN): they seem good, yes, but the HP-15C was... mmmh... better. Now I can say why. Thanks, Karl. -- Antonio No calculator is better for me than the 15C. Hope either HP or someone else will reissue it, identical or improved, but I'd like to feel the same sensations when I hold it in my hands. ▼
06-13-2006, 02:14 AM
Antonio -- Thank you for the compliment. It's a topic that's been rattling around my head for a while -- one which I felt has not been fully appreciated by even today's so-called "professional" designers of calculators. As evidence, consider the HP-33S as well as the incoherent and incohesive low-end "student learning assistants" being sold for US$15 today. So, the front-panel images being presented gave me a reason to formulate the "short essay". I might turn it into an article by stipping off the contemporary commentary and adding something more of substance. Best regards, -- KS |
