Re: X, Y Z & T--should there have been more? Message #17 Posted by C.Ret on 26 June 2012, 4:51 a.m., in response to message #16 by Gilles Carpentier
You are right Gilles, that's make RPL much easy to use and to trackback what operation we push into!
Even an of simple HP28C/S, the relatively small graphic display makes all the stuff to be key-in easy. No one have to worry about stack depth or memory or 'what is in the stack' at each step. Just have to quick watch stack to reconize numerator, denominators, intermediate result or last operation intermediate result !
For a better illustration of the process, I post the step by step captures of my HP28S display.
[f][CLEAR] |4: |
|3: |
|2: |
|1: |
[3][ENTER] |4: |
|3: |
|2: |
|1: 3|
[1] |3: |
|2: |
|1: |
|1_ |
[+] |4: |
|3: |
|2: |
|1: 4|
[4][ENTER] |4: |
[3][+] |3: |
|2: 4|
|1: 7|
[*] |4: |
|3: |
|2: |
|1: 28|
[2][,][6][+] |4: |
|3: |
|2: 28|
|1: 8|
[4][ENTER] |4: 28|
|3: 8|
|2: 10|
|1: 4|
/4:\\\\\\\\\\\\\\\\\\\\28/ (*) Not show on HP28C/S display only
[6] |3: 8|
|2: 10|
|1: 4|
|6_ |
|4: |
[+] |3: 28|
|2: 8|
|1: 10|
[*] |4: |
|3: |
|2: 28|
|1: 80|
[+] |4: |
|3: |
|2: |
|1: 108|
[2][,][3][+] |4: |
|3: |
|2: 108|
|1: 5|
[2][,][1][+] |4: |
|3: 108|
|2: 5|
|1: 3|
[*] |4: |
|3: |
|2: 108|
|1: 15|
[3][,][5][+] |4: |
|3: 108|
|2: 15|
|1: 8|
[4][,][2][+] |4: 108|
|3: 15|
|2: 8|
|1: 6|
[*] |4: |
|3: 108|
|2: 15|
|1: 48|
[+] |4: |
|3: |
|2: 108|
|1: 63|
[/] |4: |
|3: |
|2: |
|1: 1.71428571429|
Note that after a few entries, I no more use the [ENTER] key, as du to long use of the HP28S keyboard, I prefer using the comma ( [,] key) or space ( [SPACE] key) to separate numbers for immediate operation.
I use to do this ‘immediate operation’ style entry as my current way to enter and think about keying, that in the first watch of the problem, I have not understand that this formula is a problem on 4 stacks level limited RPN calculators.
During the ‘immediate computation’, the arguments are push during the transitory process into the stack, but this is not display. That makes me believe that only 4 stack levels are mandatory. In fact a bit more! To clearly illustrate the need of quite 6 level, I may have intentionally put on extra [ENTER] pushes (i.e [4][ENTER][6][ENTER][+] )
But making this, I will have point out the painful unlatching behavior of the command entry line systems (RPL, HP30S, etc…) compare to truly RPN stack entry system (real RPN stack behavior) !
Edited: 26 June 2012, 4:56 a.m.
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