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RPN(HP-31) vs AN(TI-57)
02-10-2020, 12:23 PM
Post: #1
RPN(HP-31) vs AN(TI-57)
An excerpt from Interruption as a Test of the User-Computer Interface, JPL Proc. of the 17th Ann. Conf. on Manual Control; pg.655-667, NASA-N82-13721, OCT 1981, 13 pgs.

"SUMMARY
     In any practical interaction with a computer, the user is required to formulate, phrase and enter the problem for solution through a series of steps. One very common and important characteristic of this procedure is that the operator may be interrupted at any point and required to attend to other tasks before resuming. Such interruption could have pronounced effects on the time and errors made while completing the computer task.
     In order to study the effects different logic systems might have on interrupted operation, an Algebraic calculator and a Reverse Polish Notation calculator were compared when trained users were interrupted during problem entry. The RPN calculator showed markedly superior resistance to interruption effects compared to the AN calculator although no significant differences were found when the users were not interrupted.
     Causes and possible remedies for interruption effects are speculated. It is proposed that because interruption is such a common occurrence, it be incorporated into comparative evaluation tests of different logic system and control/display system and that interruption resistance be adopted as a specific design criteria for such design.

METHODOLOGY
     The Hewlett Packard Model 31E and the Texas Instrument Model TI57 hand calculators were chosen as examples embodying the RPN and the AN logic, respectively. Both calculators are examples of scientific calculators equipped to solve problems of considerable formulation complexity."

Sample equation, chart, table, graph, etc as well as simple program(s) documenting the comparison are included.

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02-15-2020, 10:43 PM
Post: #2
RE: RPN(HP-31) vs AN(TI-57)
I'd be really curious to see how algebraic expression entry calculators (TI-84, Casio fx-CG50, HP Prime, etc.) compare in the same test.
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02-16-2020, 01:53 AM
Post: #3
RE: RPN(HP-31) vs AN(TI-57)
(02-15-2020 10:43 PM)Dave Britten Wrote:  I'd be really curious to see how algebraic expression entry calculators (TI-84, Casio fx-CG50, HP Prime, etc.) compare in the same test.

Since you enter the entire expression before evaluating anything, you'd see exactly where you left off. Example:

((5+2)*7 /( 4+ ...interrupted

continue (you don't have to complete right parentheses in most cases)
3) =

Tom L
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02-16-2020, 02:04 AM
Post: #4
RE: RPN(HP-31) vs AN(TI-57)
(02-16-2020 01:53 AM)toml_12953 Wrote:  
(02-15-2020 10:43 PM)Dave Britten Wrote:  I'd be really curious to see how algebraic expression entry calculators (TI-84, Casio fx-CG50, HP Prime, etc.) compare in the same test.

Since you enter the entire expression before evaluating anything, you'd see exactly where you left off. Example:

((5+2)*7 /( 4+ ...interrupted

continue (you don't have to complete right parentheses in most cases)
3) =

Right, that's why I suspect the interruption would have less of an impact with that scheme compared to the uninterrupted users, but I can't say how the overall averages would compare to the other input methods.
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02-16-2020, 03:41 PM
Post: #5
RE: RPN(HP-31) vs AN(TI-57)
Interesting discussion...I agree that being able to see a full equation allows the operator to verify that this was the intended math. On the other hand, an operator using RPN, I feel (from my own experience) is much more intimately involved with the math being done. It reminds me of a discussion going on in the meteorology forecasting community concerning looking at computer real time surface analysis vs hand drawn analysis. At the SPC (NOAA/NWS’s Storm Prediction Center), the forecasters are encouraged to preform hand analysis as it is felt that this involves the forecaster to a greater extent into a full awareness of the initial atmospheric state.
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02-16-2020, 03:48 PM
Post: #6
RE: RPN(HP-31) vs AN(TI-57)
...to be clear, I am comparing text book vs RPN entry. I find algebraic entry prone to symbolic error (did I handle ()’s correctly), but not satisfying in being intimately involved from a math viewpoint.
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02-16-2020, 05:22 PM
Post: #7
RE: RPN(HP-31) vs AN(TI-57)
(02-16-2020 03:48 PM)lrdheat Wrote:  ...to be clear, I am comparing text book vs RPN entry. I find algebraic entry prone to symbolic error (did I handle ()’s correctly), but not satisfying in being intimately involved from a math viewpoint.

It depends on the calculator. The algebraics with an input line let you see the full expression, although it is still possible to make mistakes, e.g. -2 ^ 8 versus (-2) ^ 8.

Algebraics without an input line will indicate that you've exceeded the stack size of pending operations or exceeded the maximum number of nested parentheses. An RPN calculator with a fixed copy-down stack will silently lose stuff off the top of the stack and produce incorrect results it you enter an expression that is too complicated.

— Ian Abbott
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