We don't want this (and I'm fairly sure I speak for Faculty and Students alike)ĭon't get me wrong, color and higher resolution would be nice, but I'd much rather they sell the current device for what is more along the lines of what it costs to produce. We've been talking, they haven't been listening. So when calculator users are already used to it for single operands, why not use it for two, like RPN does?
If you've already added 42 and 18 to get 60, and need to take cosine of that, it does not make sense to hit "STO 1 COS( RCL 1) =" instead of just "COS". The advantage is that when you need to use the result of one calculation, you don't have to store it. To get sin(90), you typically enter 90 SIN. If you don't, it won't do you any good, and will even prevent you from faking it.Īlso, most non-RPN calculator are still reverse in how they handle single-operand calculations. In other words, if you know basic arithmetic well enough to do it on pen and paper, you should feel at home using RPN. You get the same intermediate results too. And if someone told you to calculate (4+7)*(11+31), you would first take 4 and 7, add them, then take 11 and 31 and add them, and finally multiply the results. If someone told you to do 23 x 27, you would likely write down (or memorize) the two numbers and then do the multiplication. It's how you would do it without a calculator.
I could easily explain why it requires fewer keystrokes, but why exactly it requires less cognitive effort is harder to describe. That's not exactly right, but it's as close as I've been able to come. With infix you have to manage the "stack" in your head, figuring out when to add and remove nesting levels with parentheses. At each point along the path you only have to remember where you've been and where you're going.
I believe, though, that it's because when you use RPN you pick a "path" through the expression, and then just follow it. On only one of the five problems was the RPN calculation not correct, while the infix calculation was incorrect on three out of five (determining which answers were correct took significant time and much arguing).īottom line, per our impromptu tests and my personal experience, RPN is faster and easier. To top it all off, actually punching all those keystrokes into real calculators showed that RPN was more accurate. The infix guy, on the other hand got badly bogged down, backed up several times and ultimately gave up after his RPN competitor had been watching him struggle for five minutes. Two more stepped up to try and, once again, the RPN user wrote down keystrokes in a long list, without any more hesitation than it took to find his place in the expression. It had fractions nested at least ten layers deep and was, frankly, ridiculous. Then someone (I think it was actually someone from the RPN camp) decided to write a truly horrendously complex expression. The RPN user consistently finished 25% faster than the infix user, even though the keystroke list was only about 5% shorter. In contrast, the RPN-er never paused, never hesitated, just wrote down keystrokes as fast as he could.Īfter that, we all decided that we should also time the remaining trials, which were all conducted with different candidates.
FREE42 TRIG FUNCTIONS DISAPPEARED HOW TO
Everyone watching noticed that the infix-proponent often paused for a second or two to think about how to handle the next bit, or stopped for a moment to go back to count up parentheses. In all cases the RPN keystroke list was shorter, often considerably, but after the first was done everyone noticed a second interesting and unexpected outcome: The RPN-wielder finished writing down his keystroke list long before the infix-wielder - and not just because of the number of keystrokes.
FREE42 TRIG FUNCTIONS DISAPPEARED SERIES
Each was to write down on the board, under the expression, the series of keystrokes that would be needed to evaluate it. Then for each expression, two candidates were selected, one from the RPN camp and one from the infix camp. One guy got on the whiteboard and wrote down four very complex arithmetic expressions.
A measurable claim like that immediately sparked a demand for proof, so we decided to do some comparisons. Late one night the discussion got somewhat heated and someone said that an advantage of RPN was that it was faster because it required fewer keystrokes. I was an RPN-lover even then, having recently graduated from my 15C to a 28S, but most of the other geeks in the university computer lab where I spent a ridiculous amount of time couldn't see the sense in it. I don't know that I can really articulate it, either, but I can report the results of an interesting experiment I participated in about 20 years ago. So I ask: Why do you, Slashdot users, like RPN?
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