bob@dolores.Stanford.EDU (Bob Lodenkamper) (03/12/91)
In article <7645@mentor.cc.purdue.edu> ahernsd@mentor.cc.purdue.edu (Dynastar) writes:
Also, to start a new topic: being used to RPN as I am, I find
it frustrating to use a "normal" calculator and find myself
constantly typing 1 = 2 + for example to add 1 and 2. Am I the
only one in the world who feels that RPN is the intuitively
obvous way of doing things?
It not intuitively obvious at all, but once RPN is burned into the
fingers there is nothing more irritating than using an algebraic
calculator, having an intermediate step of a calculation in the
display and pressing 2 /, thus losing everything I've done so far.
- Bobfrechett@spot.Colorado.EDU (-=Runaway Daemon=-) (03/12/91)
In article <BOB.91Mar11161503@dolores.Stanford.EDU> bob@dolores.Stanford.EDU (Bob Lodenkamper) writes: >In article <7645@mentor.cc.purdue.edu> ahernsd@mentor.cc.purdue.edu (Dynastar) writes: > only one in the world who feels that RPN is the intuitively > obvous way of doing things? > >It not intuitively obvious at all, but once RPN is burned into the You don't think that RPN is intuitively obvious.. Think about the way that you do operations on a piece of paper. Do you arrange the numbers in some logical format and then apply the operation to it? Or do you look at the first number only and then the operation and somehow apply that operation to the next number which you don't know yet? The latter is what normal algebraic calcs are really trying to do. Looking back on it, I find that it really isn't very easy to think like that.. I found that when I used algebraic entry that I many times have to write it all down on paper so that I don't get order of operations all messed up. Also consider that when you do work on a CASIO or some such that you have either have to write down your scratch work alot, or make extensive use of the ONE memory location so that you can use your results later. On an RPN machine however, you can just leave your scratch work on the stack and pick it out and use it whenever you want.. I think that it is much more intuitive. It is how my brain works. What would you think if you were brought up on RPN and then switched over to an algebraic calc? ian -=Runaway Daemon=-
bob@dolores.Stanford.EDU (Bob Lodenkamper) (03/12/91)
In article <1991Mar12.014121.925@csn.org> frechett@spot.Colorado.EDU (-=Runaway Daemon=-) writes: In article <BOB.91Mar11161503@dolores.Stanford.EDU> bob@dolores.Stanford.EDU (Bob Lodenkamper) writes: >In article <7645@mentor.cc.purdue.edu> ahernsd@mentor.cc.purdue.edu (Dynastar) writes: > only one in the world who feels that RPN is the intuitively > obvous way of doing things? > >It not intuitively obvious at all, but once RPN is burned into the You don't think that RPN is intuitively obvious.. Think about the way that you do operations on a piece of paper. Do you arrange the numbers in some logical format and then apply the operation to it? Or do you look at the first number only and then the operation and somehow apply that operation to the next number which you don't know yet? The latter is what normal algebraic calcs are really trying to do. Looking back on it, I find that it really isn't very easy to think like that.. I found that when I used algebraic entry that I many times have to write it all down on paper so that I don't get order of operations all messed up. Also consider that when you do work on a CASIO or some such that you have either have to write down your scratch work alot, or make extensive use of the ONE memory location so that you can use your results later. On an RPN machine however, you can just leave your scratch work on the stack and pick it out and use it whenever you want.. I think that it is much more intuitive. It is how my brain works. What would you think if you were brought up on RPN and then switched over to an algebraic calc? I failed to include the obligatory "your mileage may vary." Oops. Since I find it impossible to use algebraic calculators having used RPN, I must grant the ability of RPN patterns to displace algebraic, but in my pre-HP days I certainly was able to get things done on an algebraic calculator. Either will work, depending on what one is used to... Remember the older RPN calculators only displayed the x register, and I see little difference between having to remember what's on the stack and putting in all the silly parentheses required by an algebraic calculator. The 4 line display may be the single most useful innovation introduced in the 28. - Bob
alan@ukpoit.co.uk (Alan Barclay) (03/13/91)
In article <BOB.91Mar11161503@dolores.Stanford.EDU> bob@dolores.Stanford.EDU (Bob Lodenkamper) writes: >In article <7645@mentor.cc.purdue.edu> ahernsd@mentor.cc.purdue.edu (Dynastar) writes: > > only one in the world who feels that RPN is the intuitively > obvous way of doing things? > >It not intuitively obvious at all, but once RPN is burned into the > I would say the both systems are equally obvious, it's just that we are used to one system or another, after all if someone asks you to 'take 3 and 4 and add them' it's obvious what he wants to do. Equally 'Take 3 and add it to 4'.
roy@phri.nyu.edu (Roy Smith) (03/14/91)
Good old accountants' adding machines (the mechanical types, anyway)
are RPN (or at least a subset thereof). To add 45, 12, and 109, you do: 45,
enter, 12 plus, 109 plus. There is an equal key (usually labeled "total"),
but it doesn't actually perform any operation, it just shows you the last
result, which is typically stored away in some internal register (gear
bank?) and not printed on the paper tape by default. OK, the "enter" after
the first number is actually a "+"; so think of the total key (from the last
operation) as "display x, 0, enter".
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
"Arcane? Did you say arcane? It wouldn't be Unix if it wasn't arcane!"stevev@greylady.uoregon.edu (Steve VanDevender) (03/14/91)
In article <BOB.91Mar11202926@dolores.Stanford.EDU> bob@dolores.Stanford.EDU (Bob Lodenkamper) writes: Remember the older RPN calculators only displayed the x register, and I see little difference between having to remember what's on the stack and putting in all the silly parentheses required by an algebraic calculator. The 4 line display may be the single most useful innovation introduced in the 28. - Bob I have one of the oldest HP calculators, an HP 9100A. It has only a three-level stack, but displays all three stack registers. There's even a small lighted sign next to the CRT that labels each register: --------------------------------------- | -8.888 888 888 -88 | z temporary | | -8.888 888 888 -88 | y accumulator | | -8.888 888 888 -88 | x keyboard | --------------------------------------- So a labeled multi-level stack display isn't THAT new. The 9100A also has RPN a little different from its successors, in that stack lift and stack drop are not automatic (although there are keys for doing either). All input goes into the x-register, overwriting its original contents. +, -, *, and / operate on x and y and return the result to y, leaving x and z intact. Most functions of one argument operate on x and return a result to x, except for |y| (now known as ABS), which takes the absolute value of y and returns it to y. The 9100A also has the original form of synthetic programming--the program and data registers are not partitioned so it is possible to make self-modifying programs. Since the 9100A does not have subroutine calls, this was undoubtedly used to advantage in some circumstances. -- Steve VanDevender stevev@greylady.uoregon.edu "Bipedalism--an unrecognized disease affecting over 99% of the population. Symptoms include lack of traffic sense, slow rate of travel, and the classic, easily recognized behavior known as walking."